You would THINK so but some of the "smallest" revisions made the biggest changes.
Pretty much all of the standard (single) cabs are the same from 1981-up.
Prior to that (1972-1980) the manual trans and 4wd trucks had a bolt-in floor hump, while the auto 2WD trucks have a low, stamped-in hump.
In the '72-'80 cabs, the hole in the firewall for the Heater-A/C box set-up is way different, too.
If you get one that's pre-1988, then there's no holes for the clutch master bracket above the pedal support, but you can weld it in or drill holes.
Anything prior to '88 will also require moving the wire harness over for a MANUAL transmission application, since the wiring was in the way of the clutch master cylinder.
Simple answer? LOL
For simplicity, stick with 1988 up 4wd or manual transmission cab.
Mark.