Hi Kyle,
I just put a stereo in my '90 745 a couple of months ago. The stock stereo was not Pioneer. The bezel was not useable on any other deck. The one on your Pioneer may be. The adapter I got from Crutchfield had a piece in the middle with holes for shaft mount radios that could be removed for DIN decks.
Another issue to watch for is that there seems to be some confusion in the aftermarket industry about which wiring harness you need for different years of 740's. Earlier years used plugs that were about 5/8 square. Later ones(including mine) were rectangular about 1/2 x 1 1/2. I don't know when they changed. The wiring harness kit from Metra for my car only included the harness that attached to the back of the deck. I also needed the one that bypassed the factory amp. The kit from Crutchfield included both. If your present deck is not factory, you may just be able to use the wiring harnesses from it.
I hope this is helpful.

Dane Klaproth