In reply to Oops, the date code is indeed by Fairfaxwatchhunter
Thank you for confirming the date code as M3. Yes, this changes the date of the watch to 1963; unless the movement inside is dated differently.
I am not sure how to proceed with this ID, since the 'Centennial' model name is not in the 1964 or any of the other earlier pricelists we have. The 13221 model number is assigned to the Drake B for 1964, but clearly it was also tagged to the Centennial. Since the next oldest pricelist we have is 1961, and we are missing the 62 and 63 lists, then perhaps the Centennial and Drake were sold at the same time in 63. I have seen in the pricelists were Bulova used the same model number with different model names, so this is a possibility to consider. The other difference is that your model has the stainless back instead of gold plated.
Perhaps Centennial was a short lived model in the early 60s, or possibly omitted from the pricelist by accident. Bulova's Centennial year was in 1975.