Yes they are, the only difference between a 2wd and 4wd burb body is the tranny tunnel. The 2wd is lower than the 4wd so you have 2 options if your doing a body swap
a)put in a 2" body lift
b)cut out both tranny tunnels and put the 4wd tunnel in the 2wd tub
Reason for this is for clearance for the tcase. I just did this kind of swap February of 2003 (lots of pics in my webshots). I put a 81 2wd burb body on a 77 4wd chassis.