mint,
Welcome to this forum. You have a very nice catch.
You have an I frame ".32 Hand Ejector", known to collectors as a 6 screw Post War 3rd Model Transitional. It is a pre model # gun but is 2 versions earlier than the 'Pre-Model 30' which was the Model of 1953 .32 HE New I frame. The Mod 30 designation was ordered in June 1957. I too would agree that a $50 letter is not justified.
Serial #s in my database with confirmed shipping dates would place the birth of yours in the 1st half of 1951. By the latter half of 1951 it was "Improved" and known as such to collectors, by having the leaf spring replaced with a coil spring and the 6th screw on the fore strap of the grip frame was deleted.
A ball park figure on the value would be ~$300.
Bobbed hammers such as yours have been made very useable for single action shooting by serrating the top surface which provides a purchase for the thumb to cock the hammer.
Hammers are not difficult to find on e-bay and Gunbroker. Post war .32 and .38 S&W I frame and .38 Special J frame hammers up to the Model of 1953 will match. Beginning 1953, I and J frame hammers will still interchange but have different spur shapes:
Model 1953 I & J new style standard hammer on left, old style hammer on right:
In 1962 the hammer to spring strut junction changed from the ball/socket to the fork/pin (at #295,000 on the Chief Spl.) and can be used by swapping out the inexpensive spring strut as well. Hammers from this period until replaced by the MIM hammer w/o the firing pin in c. 1998, will still interchange.
To see a comparison of the hammer strut differences scroll down at this link:
S&W J Frame - Imgur
Forked strut shown w/o spring & retainer:
Even a pre war I frame centerfire hammer will work with a slight notching modification for the post war hammer bock safety bar.
Hope that helps,