What he said. Certainly closer to '66 than a '56, and with a lot of non-stock parts on it. Looks like someone "customized" it at some point. Probably started life as a 250 Scrambler. Does it say "250" on the other side of the engine on the cam cover? Not all that rare, not in good condition, not worth all that much as far as Ducatis go, but then I'm no expert either.