HEY I ran into this a couple time's , the early 67's have a slightly different opening in the tailpan , it is like this
early 67 style will ONLY fit early 67 ORIGINAL tailpan and have the correct key position
late 67 style and 68 are the same and if you try to swap them it make's your key sideway's ,
my 67 RS has a build date of 10 E (OCT 1966) and it has the early style , I still have my original ignition and door / glove box lock's and even the original rochester key's and mine are an A and a B ,