I've seen variance on the rear brackets that mount to the floor. The only difference I've seen in a Stroppe vs. Hickey (and later Luben/Stroppe) is the material matching the Bronco pleats and the little brackets that the cushions screw to. Pleats and no tabs, is really what identifys the Stroppe seat. At least thats what I've seen. I've had 3 Bajas with STroppe installed middle seats and they all had no tabs and had pleated seat face. It could be though, that whoever was making them made them and changed them as the years went by. Stroppe added his material, and the design changed to the tabs later on? In any case I think they are cool, but so is the Jeep folding seat alternative for the price!