Yes, they were both available on a 383+4 Barracuda in 1971. The louvers were way more common on base model Barracuda's, I have a set on my 71 Gran Coupe. The shaker was available but only on a 383+4 equipped car. As far as I know, none were ever made, but that was as of a few years ago, one may have surfaced in the last few years. Too bad there is no tag or sheet to prove his statement.