As for the frame stamped on the bottom of the bottom bracket is SM (80 7 1779) I used info form the Trek site and the stated stamps are not apparent on the front or Rear Derailler.They appear to be original,so they would be pre 1972? The stamed number on the frame I had a hunch may have reprsented year 80/ month july /1779Th bike.
with a potential of 1778 others out there, Just makes me more curious, Global what happend
eye eye eye