I agree with you, the first one is the one shown in the '68 AIM. I've never had an automatic Camaro, but if I had to guess I would say the first one is for a '68 Camaro and the second one is for a '69 Camaro. Also, HBC says that both bracket designs replace original GM part# 3945494 which can not be correct. The original bracket part# in the '68 AIM is 396287. I don't have a '69 AIM, but someone with one could check the bracket shape and part#.
Paul