2wd carpet vs. 4wd...hump height.

[1976K5CHALET]

Okay....here's the deal. Should have the title issue worked out by years end on my 79 2wd k5. Since the body is rusty its getting scraped once i have the title. Thursday i inadvertantly walked into a deal on a 89 Jimmy for $200. Have to jump the starter but is runs and has a clear title. I'll use the motor and tub for the 79 2wd K5 project and the trans and tcase for the chalet to improve mileage and 4lo ratio. So i figure the difference between the cab floors is the trans tunnel hump. So i will save the cover from the 79 2wd tub and install it on the 89 4wd tub. But i'm thinking it can't be that easy so i need to know what the difference is since ihave never owned a 2wd i have no clue except the covers are different and before you order a carpet kit they ask 2 or 4wd. Clue me in fella's.

Doug W.