I'm certain that a lot of them are legit. Have you ever gone on rutracker? There's so many direct CD rips you can get there in flac, oftentimes with album artwork. I always try to get the full artwork for any album I download, sometimes it's a real bitch trying to find it, sometimes I can't. I doubt he takes the time to make scans, but who knows? He keeps all his 'shared' collection in zip folders, so we can't see what's inside.
I think that certain releases he has are either transcodes or just don't exist. Every once in a while I'll encounter one where I'm not even certain it was RECORDED in lossless. For example, I recently saw he had a couple Johnny Hobo and the Freight Trains CD's in FLAC. I seriously fucking doubt he does.