I've not put one on lately George but I was thinking the rear were shorter than the front base screws. I think that one end of the front base is thicker than the other and that's the one the longer screw goes in. I don't think it matters which screw goes where in the front base but I seem to recall one is a blind hole and the other I can't recall. For sure the short ones go to the rear base and the longer screw the front base.