Thank you all for the insights. I'm new to the world of vintage watches and Heuer watches in particular. I think I will try and find a new white trim ring with the 1/5 second demarcations and just get the watch tuned up (no buffing... I promise!). Does anyone have a suggestion for finding parts other than buying a donor watch? TAG Heuer claims to offer services for vintage models, but I'm not sure how connected they are to their Heuer heritage.
Once again, I thank you all for your help and look forward to my current journey with my dad's watch and perhaps adding a few new examples to my collection.