P-100s and P-90s look the same from the surface. No way to tell them apart. P-100s will be dead quiet when only using one pickup because they're a stacked humbucker design. Not a bad pickup, just not P-90s.
That's a pretty nice looking LPS. I couldn't find a word of information on them online either. Rare, but unpopular perhaps? My preference is for a bound fingerboard on the LPS but for $900 that's easy to look past. If you like the way it plays and dig the sound my opinion is it's a solid investment.