its not a scam to sell it, but you'd be part of a scam if you use it. Putting a write off back on the road or playing match the VIN # would be a scam. The police may never check a VIN in a pull over, but the insurance company would in a serious collision before paying out.
But there are guys selling stolen ownerships, track bikes that used to be stored at a condo...... and every year a few get caught with no licence or insurance so there is a market for everything. One motorcycle show I was at had blank pink insurance tags, you type up your own info.