Have you tried right clicking on the pics that you originally saved, scroll down to "View Image Info"? You may find the website you found them on listed or some other clue as to where to locate the pics... if the website still exists.
I don't think there is a "lift" in the bus. Based on some of the car haulers that were at the racetrack we worked as food vendors in N. GA, it looks like they simply built a 2 piece heavy deck with a heavy duty piano hinge (one piece folds over onto the interior side of "upper" tailgate). The sloping ramp probably holds tools etc under the raised section. The tailgate is probably "pinned" possibly with a bent arm pin
in place with the upper window section closing over the tailgate.