I noticed a lot of posts disappeared. There must have been some server problems and a restore done. Yes, it's possible for a 68 RS with the 327/275 hp engine and 4 speed to have a 12 bolt rear. If it was an automatic with the 327/275 engine it would have had the 10 bolt. CRG has a special article on the L30/M20 combination on their website(
www.camaros.org).