The register capacity is absolutely the right thing to go by in aging a Camaro (or a Carrera or Autavia come to that).

The Camaro seems to first appear in catalogues in 1967, as either a 7220 Camaro 12 sporting 3 registers with max 12 hour recording capacity (and the very rare 7228 18K gold variant) or a 9220 Camaro 45 with 2 registers and 45 minute capacity. The range thus mirrored the already existing Autavia and Carrera 12 and 45 ranges. The Camaro also used the same stalwart Valjoux movements as those existing models too - Val 72 for the three-register models and Val 92 for the two-register 45s.

Then, in the 1970 catalogues, watches powered by the Valjoux 7730 replaced the 45s in all three model ranges. These new watches have 30 minute recording capacity and Heuer referred to them as Camaro 30s for that reason. The 12 models continued alongside the 30s, still using the Valjoux 72.

The 7730 was superceded by the 7733 pretty quickly, as reflected in the model designations for these watches - 73343 (steel) and 73345 (gold-plated), the first three digits designating the movement in the watch. It should be noted that the 7730 and 7733 don't feature a date wheel, so for Camaro 30s with a date window, the movement is actually the 7734 and correspondingly the model number becomes 73443 as a result.

Here's a page from the 1970 US catalogue showing these Camaros:

So the Camaro 45 would appear to run from 1967 to 1969, with the Camaro 45s from 1970 to 1972, which is when the model last appears in Heuer literature.

Hope that answers your questions, but feel free to add any others!