Definitely look before you buy. I know a guy who purchased sight unseen. We told him to go and look at it. He got pictures and the dealer responded to all his emails. It was all lies. The pictures were doctored and the replies were lies. He was given a lemon and it was not a good result for him.
Don’t let your emotions get involved and keep a level head. If you do purchase preowned, run your hands along the outside edges/corners or the mirrors, pegs, levers, exhaust tips, etc. If there’s only one key, and he tells you he lost the other, it’s probably a salvage bike.
If it’s Ducati Miami or the Dealer that owns Pureducati.com, stay away.
Ducati Miami tried to sell me a 996 Monoposto and state you can ride a passenger on it; while the monos come with an aluminum frame.
The dealer in Pompano’s answer to ever question I asked was, “I’m not sure. I’ll have to check and get back to you.” There was also no exemplary client service, and I’m big on that; especially when making such an amazing purchase as a Duc.