My coworker is selling both his SPAS 12's. I am interested in the shorter top SPAS. He is asking $600 for the top and $700 for the bottom. Does anyone have any tips/clues to look for? Any owner opinions on these? I briefly saw AM letter markings on top just past the reciever... is this the manufacture date of mid 80's?? I have heard of these makes and models but am complety in the dark as a potential buyer.