Yes, and a very beautiful 38/44 Heavy Duty indeed! I can provide you some basics, but there are HD experts here on the Forum who I hope will provide the details.
First, its full name is the .38/44 Heavy Duty Model of 1950, or sometimes referred to as a Pre-Model 20 . . . the model number assigned in 1957. Its name reflects the fact that it is chambered for the .38 Special but made on the .44 "N" frame which is larger than the M&P's "K" frame. Your .38/44 Heavy Duty is equipped with fixed (service) sights but this same .38/44 was made in the same timeframe with target sights and is know as the .38/44 Outdoorsman Model of 1950 or the pre-model 23.
The serial number would indicate it was a late 1953 or perhaps an early 1954 ship date . . . only a factory letter can provide confirmation of when and where it shipped.
I'll leave . . . "the rest of the story" to the experts.
Enjoy that beautiful Heavy Duty,
Russ