Waterproof Case measures 42mm lug to lug x 34.5mm non inclusive of the Crown using Calipers. Oversized Crown. Caseback screws on and is stamped as shown. Military style Stainless Steel Case by Star Watch Case Co. 23 Jewel Chronometer. Hackset for synchronization.
This post led me on a multi-year search that finally yielded fruit. I finally have a Transportation Special Bulova of my own. The watch I purchased was 'almost' complete. It is most similar to your stainless cased watch, but was missing the 'balance protector bridge' (for lack of a better term) that your stainless variant is also bereft of, but that your gold variant has. After a bit of digging around, I was able to locate one from a 10BNCH donor movement (no longer functional).
My watch has the micro-adjuster intact and functional, along with the accompanying swan neck tensioner. Additionally, my watch included an inner dust cover that fits between the movement and case back. My case serial is stamped M0 like yours, but my movement is stamped N4. LOVE this watch and will try to get pictures posted in the weeks ahead. Just wanted to say "thank you" for a few years of frustration, and a lightened wallet. ;) It's my new daily driver, and I don't see that changing anytime soon.
~Tommy