As I understand it, they are all basically the same saw with slight differences in the engine size. Early on some had a 42cc engine, the standard WoodBoss had about a 47 cc engine, and the WB Super had . . . I don't know . . . something slightly bigger than 47cc perhaps. Some of these other guys can tell you more specifics, and some of them will holler and cuss at you for not going through old threads to find the answer.
I asked recently what were the specific years of production for the 028 line, and no one gave an answer. My guess was 1970s through early 90s.