Which shop had that for a month at that price? That's a quick sell guitar at $1500 to $1800, more on a used retail sell through a shop, and I don't know of a single pawnbroker that gambles that kind of money and doesn't know exactly what he has. GC would have paid more for it than that as a walk in buy.
The reason I say that is there are tons, and I mean tons, of Chinese fake high end guitars everywhere around here hitting alot of shops. There's also some shops that are knowingly selling one about every 6 months like they came in on pawn. I've seen 2 LP Customs that had all the paperwork and everything that looked good, but were easy to spot because of the rosewood boards instead of ebony.
I don't know enough about PRS stuff to say, but I would get it checked if I were you. Pawnbrokers around here (and you're in my area) know thier business or they wouldn't be in business.
I honestly hope it's real and clean and you scored the pawnshop lottery of the year, but knowing the the pawn game, something doesn't sound right about thier pricing and it hanging for anywhere near that long without a buy.