That would be funny as I have a road Principia and I love it so I was looking for a track Principia. I found one for cheap and received the frame with a crack on the head tube, luckily fully refunded. After that I've gave up on track Principas as the they were too expensive so that would be wonderful if it's a frame made by Principia manufacturer.
The bike was 6,8 kg with tubular wheels so I can assume that it could be some better sort of frame.
This purchase was full of surprises too. The original fork was listed as carbon, because it doesn't attract magnets, but was full alloy. The tubs on the original wheels weren't glued correctly so it fell off as soon as it got flat.