Putting 4S covers onto 4S guts: OK to just replace logic board not the rest?

Question

I have 2 Iphone 4s': A black non-working iPhone 4S in perfect physical condition, and a white cracked-screen-but-working iPhone 4s. I want to put the black's front and back covers onto the white phone. I have followed tutorials closely and have the black phone taken apart as far as getting the logic board out. Before I go further -- and there are a number of additional steps still -- I'm wondering: Can I just take the white phone apart down to its logic board, then swap that logic board into the black phone , then put the black phone back together, using its existing parts? Or do all the parts from the white phone have to go together into the black's covers?  (This is assuming -- which I'm pretty sure is correct after much advanced troubleshooting -- that the problem with the black phone is in the logic board and its attendant parts.)
The point of this would be to prevent taking the black phone all the way down to its covers, which involves a number of steps past where I am. Currently I have the logic board out of the black phone (and the preceeding parts of the procedure involved in getting to it), and ready to receive the white phone's logic board (if this would work), then go back together.
Would this work, to just swap logic boards?
Or do all the parts in the white phone have to go together into the black shells?
Hope this makes sense, I'm waiting tools in hand, thanks very much for any help.
Please be sure of the answer or I'm screwed :-).
Thank you!
Neil

Answer 1

Try asking on ifixit.com's forums. You're not going to get much help here.
The iPhone is not cosidered user servicable.