From the seventies and eighties, the battle was between reynolds and columbus - both are really good, and you can't go wrong with either. The identification of any without a tubing sticker is pretty tough. They are still duking it out today, btw, but there are several other topline tubing makers in the battle now. Probably your best bet is to find one in original paint and parts mix (not that hard, really) and then find the reference catalog on the web (bulgier.net is invaluable). counterfeit bikes are not unheard of, but usually way too much trouble to do very well, for such small renumeration.

Oh, hey! if you are looking for the schizz, look for columbus KL or reynolds 753. Style points are way up there with either tubeset.