the frame horns are quite different, and without modification of the horns themselves or the bumper itself they will not swap over.
0HOWEVER... I believe that the gen 2 89 to 92 have the same frame horn and bumpers will bolt up no issue but will not look right due to the curvier body of the gen 3. but if you find an aftermarket gen 2 bumper that is built out for a winch etc, that discrepancy might not be noticable and could open some more avenues for aftermarket bumpers.
If you have a welder and some scrap metal, you might be able to fab yourself a decent bumper for it. several members here have done great jobs with that. take a look at Curious Hounds front bumper. 85 Ranger 4x4, Uncle Gump, and Lil Blue Ford have really nice fabbed rear bumpers. also TRS 2 from some guy named James Oaks has a nice front bumper
AJ