I have a Hamilton Model 21. The serial number is 2E 116XX. The s/n is located on the face just below the '60' mark on the seconds ring and no other markings. I was told this was done on 21's for the Army. Is this correct? Would someone also know the date of manufacture?

It would have been made in 1947 or 1948.

Thanks Tom, Any comment on US Army markings?

My model 21 is 2E11189 and marked the same way.
The Hamilton ledger shows that mine was sold to a California jeweler. By the time these were made, Hamilton was selling to non-military customers. I don't think you can attribute the instrument to the army The war was over and military demand was much reduced.

Timepieces sold to and issued by the Army and Navy are well marked on the back of their cases with a number of lines of incised military serial numbers, contract numbers, and so on.

As Jerry says, after the war when the Army and Navy contracts to the big watchmaking companies dried up, those companies turned to using up the parts they had been making for military watches in order to build watches to sell to the public so their unused parts inventories did not go to waste. It was not an easy sell though as many of the ones that were made for the military were being surplused out at almost give-away prices. It sounds like yours is one of the ones that was sold as a civilian watch by Hamilton through a jewelry store, has no military provenance, and would be just a very nice and good quality civilian timepiece.

Thanks all makes sense to me. The reason I asked was from a post https://ihc185.infopop.cc/eve/f...944/m/1211048871/p/2
If you look through it shows a plication that states civil 21 did not show an serial no. on the face. Let me know what you think