Even with engine problems there is a lot there for $500. That does not look like the original bench, but Broncos and Supercabs did come with the 50/50 split bench that pivots in the center rather than folding in one piece. Rear access is doable but not great. In my opinion the bricknose era double slider seat tracks gave the best rear access for Supercabs.
SHORT BED 4-DOOR DIESEL: 1986 F350 4x4 under construction-- 7.3 IDIT ZF5+GVOD
STRAIGHT SIX 4X4: 1981 F150 2wd to 4x4-- 300 I6 close ratio diesel T19, hydroboost brakes, Saginaw steering
BIG F: 1995 F-Superduty under construction— converting to 6.9L IDI diesel ZF5+DNE2