According to my VIN number my 3100 1/2-ton (titled as a 1950) is a 1951 model built in December of 1951... but how is that possible?

My dad worked in the Fisher Body plant in Baltimore for 35 years and "change of model" was always in September so anything built in December of 1951 would have been a 1952... right?

Also, to further muddy the waters mine has the 1952 push-button exterior door handles, but they could have been adding during the rebuild...

Any help would be greatly appreciated.

State title is when the vehicle was sold not the car/truck model year. The truck ID number is the model year of the truck.

I would guess that your 1951 truck is a collection of 1950-52 parts....which was done during the restoration. or perhaps it began life as a 1950 and found a 1951 title. The 1950 would have the old Huck brakes (adjusted at top of backing plate), a drivers side cowl vent and 9 board bed.
1951 has early 9 board bed-late 8 board bed, 80 MPH speedo,
1952 has 90 MPH speedo, no stainless on speaker grille or glove box door.
1950 production began 12-12-49
1951 began 11-27-50
1952 began 1-2-52
New car introduction was in Jan in those years.