Dumb question:

I just took delivery of what, per Vintage Trek using the serial number database, is a 610 frame (a beauty, by the way ... pics when it's built up ...) built in very late 1980. Since the 61X series didn't show up until the 1981 catalogue, I assume this bike was shipped and sold in 1981, and that would be its model year.

The question is this: the 1981 catalogue shows a 613, 614, and 616, with no separate 610. I'm pretty sure that this means that the 610 frame was the base for those three models, with the difference being how they were equipped (SunTour VX-GT etc. on the 613, up to Shimano 600EX in the case of the 616). That, in turn, means that while I have a 610 frame, I have no way of knowing which of the three models it may have been during its "first" life.

Trekkies: have I got all of that pretty much right, and if not, what have I screwed up? Thanks.