the guy in manhattan beach, harry fleenor, will charge you $25 to replace the door latch pin. If it is just unscrewed you can probably find one and install it urself. Not sure of a a part number but if you call it the door latch pin ur close.
Harry charges a lot to do a service but does lovely work. I have a friend who spent $135 at Essex Camera Repair in New Jersey to service a camera just like this and he said it came back lovely. Essex could also replace that pin, might cost less, dunno, you could ask.
By the way -- the shutter is not stiff going into 1/500 because there is something wrong -- that is normal. Pushing the shutter speed over to 1/500 engages a second spring to give the blades extra oomph, so it is harder to push it there. When you are shooting at 1/500 with those cameras the self timer does not work, so don't try.
Also, when it is set at 1/500 and the shutter is cocked you should not move it away from 1/500 without first firing the shutter.
Later rolleis had different setups, spring-wise, and you didn't have the extra bit about the top speed, but this one and the EVS model later in the early 50s did.
I would put a test roll in the camera and make sure the film feeler mechanism works -- those are those two rollers adjacent to the film spool supply section inside the camera, when you load you feed the film between those two rollers and then onto the takeup, close the camera and wind, the camera should stop at frame one.
Reattach leatherette with some sort of glue that is not permanent so you don't make life harder for later repair people.