I "played" with one of those obvious scam listings on CL a couple of years ago. The ad was for 2003 Prevost custom conversion at a super bargain price, with variations of the same ad scattered among a dozen different city listings according to the search app I used. The real giveaway was when I inquired about inspecting the coach and was told that the seller was stationed overseas, and the coach was "crated up and ready to ship" from a trucking company warehouse. A crated up Prevost? I don't think so... :)
Oh, and I found the origin of the pictures on a real Prevost resale site with the rig's "Sold" listing at almost 10 times the price in the CL ads.