Thanks all.
Beezageezauk - Yeah... that's one of the same lists I have for Chrono's, which was exactly what led me to my question. Being that the A65's were driven by the Tach drive on the rear wheel, I thought they may be of different ratio's than the gearbox driven Pre-Unit Chrono's.
So it looks like the following info I have may be correct.
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Grey Face Chronometric
A50 1963/1964 A65 1962/1963
Part number on face is SC 3313/00 1512
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Thanks for the info on the Nacelle as well. I've seen them advertised as fitting both A10/A7 & A65, but while they may fit, they are different as I suspected. Of course, the A65 version seems to be even rarer. Isn't that a surprise
Thanks again all.