Andersok
Posted October 2, 2017 - 8:05am
The pricelists from 1964 (we currently have none after that date) show the model number 13221 as the Drake B model, also at $35.95. The Centennial model is not in this pricelist. It would appear that by 1966 the watch possibly changed to the Centennial, which is not uncommon.
Can you confirm the datecode on the backside is M3 or M6?
Here are some photos of an unconfirmed Drake B model 13221 from 1963, with a RGP back instead of stainless:
Photos archived from an online sale some time ago.