Shawn,
Not that it matters, unless someone is doing a correct nut/bolt 5 Speed.
There are a few differences in the derailleur used from ‘66 - ‘73.
The ‘66 Fastbacks used the Sprint unit with smooth wheels.
The “Schwinn“ unit continued to use the smooth wheels into 1970 and maybe beyond.
The 72-73 used wheels with the teeth for better control of the chain.
My ‘70 Pea Picker with smooth wheels.
My ‘73 Sunset Orange with the tooth wheels.
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