Like most of you, I believe this is an early M2600. Earlier Worksman frames had a tighter kink in the downtube like Araya's, as compared to the comparatively smooth bend in more recent examples. There's been some variation in seat stay bends over the years, too; this white frame has some weird stays, but I've seen pictures of INBs like that, too. The drop-outs, OTOH, are definitely different from anything I've seen on a Worksman before... they may have been modified at some point, or maybe Worksman built them like that for a while?
