Mine has Grover locking tuners, and a core PRS nut. Here's a video from when I bought it (Chris you still around?) that was heavily modded and has Zex Coil pups installed too. He put it back to stock when I bought it.
Congrats, the stoptail EG is a great sounding/playing axe for sure. Back when I was gigging mine I found that all 5 pickup positions were really useful and it seemed to stay in tune all night. Hope you get a good one!
My first thought would be to call John Ingram (Orkie) and run it by him. He was, after all, one of PRS's first employees and I understand that he's still doing some of their endorser work.
First, I'd suggest that you find out exactly what the finish is. If it's poly, you might try some denatured alcohol......but not if it's nitro! You might call PRS customer service with the serial number and then ask for their suggestion.
Best of luck with it, Jim
If you happen to have an AT&T phone, or one that's unlocked, check out PureTalkUSA. We've been with them 1-1/2 years and get great reception everywhere we go. In our area they use AT&T towers but that ight be different in others.