OBS('92-'97) is a term that's been borrowed/pirated/stolen from the choker crowd. The term was coined when the '99 and up trucks came out. outside of the fact that both trucks are powerstrokes, they share very little in common. Therefore, the designation of Original Body Style was coined. We just happend to like it enough, that it was stolen from them
BTW, there is still a few body items produced by the aftermarket for the OBS trucks, you just have to be creative in figuring out what will work for ours