It's a great frame, and I agree that by 1979 A-D had most likely standardized the BB threading to be BSC (British), but I had an earlier A-D Inter 10 that was all-French equipt and most def had a French threaded BB and headset...tho it *may* have been a Swiss BB, I never messed with the fixed cup to find out. BTW as far as I ever knew there is no Swiss thread for the steerer/headset, that's either gonna be British or Italian (more or less the same) or French...so is your Puch in the famous "team green color"?