Another dirty bike for sale. For $300 it can't be clean???
If I was to guess, I'd say the bike was bought as part of a storage unit sale. You might not want the seller to have cleaned it.
It does look like a decent bike, Columbus Cromor tubing, mid-range Campagnolo drivetrain, Doppler shifters. I'd be more worried about the condition of the top tube given the location of the inlet and outlet for the rear brake cable. Any water that leaked in would have no way to exit unless the builder ran a stainless steel tube through the top tube.