Jerry, the Gran Sport has a number stamped into the left rear dropout (normally), not on the bottom bracket shell.
SN# ========= 0205247 - 1973 gransport (white & blue, older reynolds db main tubes decal)
0214823 - 1974 gransport (blue & white, older reynolds db main tubes decal)
Wow, looks like they pumped out maybe 9,000 of these bikes a year, or more.
- Don Gillies
San Diego, CA