The extended cabs and 4 door cabs for the 70's trucks really had no changes done to them, so they are all pretty much the same. I was surprised to notice that teh 1990 trucks still used the "older, round roof" cabs on the extended cabs, but the regular cabs used the "new, square roof design". I believe the it was 1982 thru their end that used the square roof on regular cabs...