My White Book says that out of the 235,147 '68 Camaros built, 40,977 got the Z22 Rally Sport package, so you're looking at just under 20% with RS. 2579 got the L34 396/350hp engine, but it doesn't say how many were RS cars. There were 30,655 SS cars built (350 and 396), even fewer than the RS cars. Looks like a RS/SS 396/350 was a pretty rare bird. Hope this helps!