Hi everyone, new member here, so here goes my first post. I am doing a ground up resto on a '68 GTX 440 hemi 4-speed Dana 60 rear. It is an AA1 silver metallic S6R Aztec maroon car. My question is that is this a rare combo? I have only seen a '68 coronet r/t like this 20 years ago and none sinse. Also on the fender tag it has ubs on the third line, mine under the u says r, under the b says 8, under the s 1. Any idea what these mean? Any info would be great. Thanks.