I have a pristeen model 28-2, serial #N523xxx that is too "new" looking to be all correct. It came with pacmyers, but my question is that it has two stampings on the inside of the right grip frame, a K inside a circle and an R inside a triangle also the number 5433. Are these factory refinish notations? There are no signs, that I can tell, that it is refinished. Appreciate your comments.