While I had forgotten that the rolling script talked about the DSII being built in secret as well, I still don't abide by the semantic rape required to transform "has begun" into "had begun" a while ago.
And nowhere is the problem of the DSII being a different design addressed either.
However, by looking at a reliable definition of the verb "to construct", we can corroborate what Mike and other people have suggested.
See:
Construct
1con·struct
verb \k?n-?str?kt\
Definition of CONSTRUCT
transitive verb
1: to make or form by combining or arranging parts or elements : build; also : contrive, devise
2: to draw (a geometrical figure) with suitable instruments and under specified conditions
3: to set in logical order
— con·struct·abil·i·ty also con·struct·ibil·i·ty \-?str?k-t?-?bi-l?-t?\ noun
— con·struct·able or con·struct·ible \-?str?k-t?-b?l\ adjective
— con·struc·tor\-t?r\ noun
See construct defined for English-language learners »
Examples of CONSTRUCT
1. They plan to construct a barn behind the house.
2. The author constructs all the stories around one theme.
3. Construct a triangle that has sides of equal length.
Origin of CONSTRUCT
Latin constructus, past participle of construere, from com- + struere to build — more at structure
First Known Use: 1663
Definitions 1 and 3, and the subsequent examples given thereafter, do support the idea that elements were already present and only waited to be assembled.
There are caveats to that though. For example, when you build a house. The more original the construction is, the more work there is to do with the basic elements.
However, some things can be explained. Take the superlaser. Would it need to be different than the DSI's?
The battle station would be wider, so you'd need a longer superlaser. I suppose some parts can be lengthened. Add several rings in order to lengthen the main conduit that would drive the beam out of the battle station. Add power conduits to feed those extra rings. Had some auxiliary power cells as well.
The dish would also become larger. Then bolt the panels with a slightly different angle.
The crust is going to be wider as well. OK. Let's assume that they link each prefab block of the crust with some transition tube or even something as mundane as a ring that's higher on one side (because it has to fit into the gap between two blocks that essentially is V shaped). Say that they used several such rings, like one per 0.01° of rotation from one block to another. Well, now you can remove a few because the angle will be smaller. It's even simpler if the transition section is flexible or mobile to some extent. You don't even have to bother, it will adapt automatically. Just bolt the prefab sections and you're done.
There are some sections which will be totally new though, and I believe it could be a stretch to pretend that the construction of those exclusively new parts would not be counted as part of the construction of the DSII itself. It just doesn't work.
However, that's already much less new stuff to build. The core for example wouldn't take much time to build.
In "X-wing Alliance", one of the levels had you attack a
Kuat space station which essentially was a Death Star core with very little structure around it. It was smaller though. But it's entirely possible that they may have had a bigger core and decided to use it for the 2nd Death Star.
Besides, the design of the DSI core would matter for the time needed to design the core of the DSII.
This is another problem. The OT:ICS shows a large spherical core with the bulb encased in the superstructure above the spherical chamber, and that bulb is even bigger than the chamber. It's very faithful, in a way, to the plan shown the in Dodonna's briefing. That said, the exhaust has to pass through the encased bulb.
http://starwars.wikia.com/wiki/File:Reactors1.JPG
The Technical Journal shows a core that's spherical, but it's considerably smaller. It doesn't show the encased bulb above the spherical chamber.
On both, the spherical core is at the center of the battle station.
However it shows the flattened chamber to be located underneath the spherical chamber, and we can see the typical bulb hanging upside down.
Etc.
I mean, there's a vast amount of inconsistency. Practically each single blueprint published at some point in the EU, for the first Death Star, has shown a different internal structure.
The AOTC:ICS drawings have shown that a Trade Federation Coreship has a flattened core like we see in the heart of the second Death Star, and the Geonosians also used a superlaser to melt ore on Geonosis (Inside the World book).
And the EU tried to retcon the other Death Star as a prototype, yet it looks like the frame we see in ROTS, which Lucas says is the ANH Death Star. Amazingly enough, its construction is quite advanced.
And then we have the plans the Rebels stole, which point to another design which perhaps never came to fruition, but obviously
did exist.
I'll spare you the story about the plans you had to steal in several games, so much that one had to be retconned, before the prequel movies, as the plans of a prototype, and the others plans as the plans of the real first Death Star.
I don't even know if they had done it properly, because the plans you stole as Kyle Katarn in Dark Forces did show the hologram of the Death Star that fit with the real appearance of the Death Star, not the plans of the thing shown during the briefing in Yavin IV's base.
Just to complicate matters, we saw the plans of a Great Weapon in AOTC, and they looked very close to the miscaled tactical rebel hologram in ROTJ, rearranged for the sake of clarity, obviously.
With all that mess, one thing is clear: the construction of the first Death Star was a big mess which alone can explain why it took so long to get it done.
As a corollary of this observation, it's possible that the Empire had many spare parts left to use for another station.
