Huh, I don’t know that it matters that much. The particular version of SDK used to compile the engine is surely the smallest part of this whole porting effort. Most of the stuff that Panda brings to the table is outside of the realm of the SDK, anyway–Panda is a 3-D graphics engine, while the SDK and its Frameworks provide fundamentally 2-D operations. If you’re programming in Panda, you probably won’t be using most of the UIKit operations, unless you go out of your way to call them directly (for instance, by using PyObjC or some such).
You could, of course, write your own Objective-C app using the full SDK and all of its interfaces, and also link with Panda to use Panda’s operations only when it suited you. Then you would largely be writing your own app using Apple’s SDK, and using Panda incidentally; and it would be completely up to you which version of the SDK you used.
But, if you wrote an app entirely in Python and Panda, you wouldn’t really see any of the SDK directly.
David