I never thought that there were so many Moto owners on this list.This has brought more out. Anyway, another consideration is the presence or absence of serial numbers. The best that I can tell, they were introduced in 1975. Grand Records started with 3322xxx on the BB shell. I think that Team Champions had a six digit one (Cause my '83 does). The number stamped into the left rear dropout wasn't a s/n. The GR and GJ headbadges that I have are of three types; plastic sort-of vertical rectangles, un serial numbered, somewhere around '71; round, "France" at the bottom, one being the aforementioned '75; and, round "Circa 1923" at the bottom, off-topic.
John Redman
Hapeville (Atlanta), GA