Hamilton pocket watch dating
All 992B had a serial number starting with C All 2974B had a serial number starting with K, or 2K, total production in excess of 16,095... 2974B production at the end of WWII was 15,5B had a serial number starting with 3C, total production of 2497 or maybe a little more... 4992B production at the end of WWII was about 95,000 more were made during the cold war,and even 'Nam.
3992B production was from 1943 to19B had a serial number starting with 4C, total production of 142,000 and higher.. The myth about the "Officer's Model" 4992B in the Coin Silver Case, is just that, a Myth. All 4992Bs in silver cases should have serial numbers from "43 ...
A lot of other mechanical watches are off that much in just one day.
The need for Railroad Watches to be "railroad approved" stemmed from a number of train accidents in the late 1800's where two trains collided head on due to poor time keeping.
Some companies (as with the Gruen Watch Company), even lost rocords to fire or other natural disaster. I am sure they had no idea that their timepieces would someday be collected.
There are several ways to get an idea of when your watch was made.
If you use it and the watch is exposed to different temperatures and shaken or turned then you will achieve about /- 15sec accuracy per week.
Write this number down and compare it to the charts on this website.
This will give a good idea of the manufacture date.
Both companies went to a different serial number system and the date of manufacture is not determinable by these letter & number serials.
: In the 1950's Bulova incorporated a symbol system to date the watches they manufactured.
It will NOT tell you the actual date the watch was acquired...