Thanks for all the input, people. I tried my luck and bid on them. Got them for some 200 dollars.
After getting them home and examining them, I discovered following:
-The shells are sprayed with some sort of granitone-like paint, so I can't be sure about number of plies, but judging from the thickness, I'd lean towards 4, rather than 3.
-22x14" BD, 13x8" TT, 16x16" FT
-They have been re-wrapped! Quite a good job, only few wrinkles here and there, but they at one time had internal mufflers, which are now gone, but there are no holes in the wrap. Why would anyone strip their drums to bare wood and then put on a wrap that looks like fake wood is beyond me, but I've seen weirder stuff. The interior paint seem to have been applied AFTER the rewrap. Also the badges look like they've been put back on, which leads me to a rather disappointing find;
-they are Imperialstars, not Superstars. Still, they look decently built, have plenty of lugs and the overall design seems very durable and functional, if simple. It is of course possible that they're Superstars with Imperialstar badges, but I somehow think that it's not very likely. The bass drum has disappearing legs and ten lugs. The high-hat pedal also says 'Imperialstar.'
Serial numbers are as following: BD 63702, TT 65057, FT 64759
Can't tell much about their sound right now, as they've got these mega-heavy Hydraulics on them and I seem to have misplaced my drumkey so I can't even tune them (or examine the wood they're made of any closer)... but the floor tom sounds very nice and insanely fat.
The Sonor snare sounds pretty good, but either I'm missing something about the strainer mechanism, or IT's missing some pieces, because it doesn't seem to work as it should. I think I might start another thread on the snare, as it's quite different from the rest of the drums.
EDIT: Here it is: http://vintagedrumforum.com/showthread.php?t=39510
Hardware is a mis-matched bunch of stuff. Hi-hat stand and straight stand are solid vintage Tama, boom stand and snare stand are contemporary cheap crap and the pedal is of course Tama Camco. I tried it a bit and it doesn't seem too extraordinary, but it's not bad either. I think I'll keep it and let go the cheap Pearl I found in an abandoned rehearsal room.
I'm still planning on selling the kit and keeping the snare, pedal, snare stand (it's totally horrible, but I really need one) and maybe the straight stand.
Before I do that, I might try and peer under the wrap, but that'll have to wait until I find my drumkey or buy a new one and since I'll be travelling for the next few weeks, that might take some time. So, judging from what we know now, what can you tell me about the kit, regarding the age, the wood, and especially the price? Other than the rewrap, it seems to be in a good shape.