The Heuer Autavia 2446 GMT ....
By: HSTE : September 13th, 2020-13:30
... in nice fall-sun-down light. The absence of the „T“ and the „Swiss“ on the subdial as well as the very low serial number (lowest so far observed one on a GMT 1st Gen) suggest this to be a potential proto-dial. Cheers, HSTE ...