I bought a "vintage" PRS (it's 30 years old which is old for PRS) for a seemingly great price and I noticed it had a big scratch on the back. I could feel that it went pretty deep into the surface but I did't see any evidence that it went into the wood. I figured it was cutting across the grain at the thickest part of the guitar and it didn't make sense for wood to crack that way. I did open the trem cavity, as it seemed to radiate from the screw hole there and I didn't see any cracks so I figured I was good. However the wood inside the cavity was dark and the lighting where I bought it was terrible so I think I missed something. Looking at photos taken in better light now I can see that there is a crack into the wood at least at the screw hole, and on the other side of the screw hole (going down into the inside of the cavity I can see a crack maybe an inch deep (See photo, hard to see but I drew a circle around it). But on the side going to the back of the guitar I don't see a crack inside the screw hole. I'm wondering if any expert luthiers here have an opinion on whether this is a wood crack going across the back of the guitar or not. I figure "who knows more about body cracks that guys who work on SGs?"