Wow, that is a really nice bike, the frame looks great. the forged dropouts indicate good quality especially for it's age, sorry I can't help more... the fork may have stampings on the stear tube but you would have to take it apart. the chrome lugs are nice too (shape is similar to that on Nishikis of the late 70s) and indicate a higher end machine. Probably double butted tange cro-mo tubing. Maybe someone else will be able to give you more info...