Campy Grand Sport & Shimano 6207 rear derailleurs

[Alidpr]

Couple of vintage rear mechs on eBay. Both in exceptional condition:

https://www.ebay.co.uk/itm/16713027...yBIFjKTSrm&var=&widget_ver=artemis&media=COPY

https://www.ebay.co.uk/itm/16712776...yBIFjKTSrm&var=&widget_ver=artemis&media=COPY

 

[fiveSixteenths]

The ‘53 mech, is there any means of telling the date of manufacture of these? Am guessing those serial number stamps, but am intrigued to know