These appear to have been designed to lesson the cost of making pistols, doing away with many of the machining operations. Had WWII gone on for a longer time, these probably would have gone into production. The Deer Gun was apparently a CIA brainchild and slated for use in Vietnam during the Vietnam War. It was even simpler in design and chambered for the 9mm Luger cartridge. It does not appear that many of these ever saw any use and most if not all were finally destroyed.
Bolts can be pretty rough and work fine.
The main thing to check is the face of the bolt around the firing pin. If it's been used a lot, there may be pitting from gas burning into the face of the bolt. If they get lined up, or one breaks, the gas pressure needed to cycle the bolt will be lost and you'll start to have serious functioning problems. Field strip the bolt carrier, then put the bolt into the carrier without the firing pin, cotter pin, or cam. Then tilt the carrier down so the bolt points toward the floor.