: Mark you have shown a catalog with the Cal 12 Monza in the older
: thread, I think it is the only Cal 12 Monza ever shown ?! Can
: you confirm the year ?

I believe the Cal 12 Monza with the Monza name on the dial was only shown in the 1978 catalogues - after that, it was the no-name "economy" version and before that only Cal 15s are shown.

By the way, the Monza Cal 15 might have been the last mainstream Heuer to be in production with the Cal 15 but it was outlived by a couple of years or so by the 15640 Skipper. The Cal 15 Skipper is still in brochures in 1983 and could probably still be bought fairly readily for at least a year after that.

And chromed 7721s were still available in 1970 certainly, maybe 1971 too, so to be strictly accurate it should probably be "first chrome-cased Heuer since 1970/1", though it becomes a matter of semantics as the 7721 was a 60s watch still being sold at the start of the 70s.