For example the Boulton uses the 19 jewel 982 movement and the Boulton B uses the 19 jewel 753 movement that replaced the 982 in 1952. There were lots of B-variants in the 1950's.
In 1956 Hamilton introduced the Paxton "B".
Then the Paxton was introduced in 1957. It was also produced in 1958.
Under the dial is a Hamilton Illinois 12/0-sized movement. I'm not that familiar with the Illinois movements from the 1950's so I'm not sure what the model number is for this movement - it says TXD on the balance bridge but that's the import code for Illinois. Imported Hamilton movements have HYL on the balance bridge. I suspect Illinois movements didn't get a specific caliber movement.
The dial was dirty, but original with a nice white finish and embossed gold numerals and markers.
The Illinois movement is Swiss-made and it's stamped ETA and 1220 under the balance. So this is an ETA 1220 - which is what I would need to know if I needed to buy a part for it.
And here it is all cleaned up and timed after a fresh overhaul, the crystal polished, the dial lightly cleaned and a new black alligator-grain strap installed.