I would also ask the seller some questions to flush out how much they know about it. If they start hesitating then it doesn't look good eg which model OCR it is eg OCR 1, 2, etc; what year it is; where they bought it from; how many miles they have done; what mechanical problems it has had; what maintenance they have done; what it cost them; what they like about it; what they don't like about it.
Five minutes of enthusiastic buyer questioning should put them on the spot or confirm it really is theirs to sell.
Good luck.