Thanks for the response Hummer. I'll check it over when I get some time and see if I can spot a serial number. I read some models have a serial number on the seat post, but mine did not. I think you're right about the Criterium model, I've come across a few of those searching for info on mine. I can't recall the exact year I bought it, but I remember it wasn't cheap (I think about 350) and I had it in high school, so that puts it before 1975. I think it was about 1971 or 72.