As others have said, the 2 and the serial number indicates 2002 production. The 10 indicates a 10 top. Beyond that, it's the way the neck is attached to the body (set neck models with maple tops are usually "Custom" or "McCarty" models), the number of frets (in this case, 22), the hardware (this has a tremolo bridge and modern sealed gear tuners, whereas a McCarty would have a stoptail bridge and vintage style stamped housings), and the controls (two hum bucking pickups, volume, tone, and rotary switch) that identify this as a Custom 22.
PRS didn't have a huge number of models back then, so it's a simple process of elimination.