Your truck would NOT "appear" to carry the wear and tear of a 1950's vintage vehicle because....
1. These trucks were sent through various rebuild programs as routine procedure. Hence, about the only thing you can actually say with any certainty was original equipment or parts would be the FRAME/CHASSIS that the Serial Number is stamped onto.
2. Depending on the level of the rebuild program, it is entirely possible that the truck was one of a "batch" that were all completely disassembled down to EVERY nut and bolt. Then the rotten parts were discarded, subsequently reassembling as many useable trucks as possible with the remaining salvageable parts, buying only what parts their project's contract budget would allow to complete a few more to "sell back" to operational units..
3. NEVER trust the odometer or hour meter records on the gauges in the vehicle.
3a. In a rebuild, both miles and hours are reset to ZERO.
3b. In the field, the motor pool sergeant would send his junior wrench-turners out to random trucks with instructions to remove and replace (aka swap between trucks) any number of whole instrument clusters or individual gauges "just for practice or training purposes". Unlike the Civilian World where "rolling back an odometer is a CRIME, in the service of Uncle Sam the practice is both common and justified.
HENCE, the only thing that the 22,000 miles showing on your truck's odometer can legitimately say is that the ODOMETER has been installed in any number of trucks for a cumulative total of miles as shown on the meter. PERIOD ! Do not ASSUME that the mileage shown came from your truck only, nor that the odometer presently in your truck is the only truck that the odometer has ever been installed in.