At the beginning of the '70 model year, there was NOT a J54 - "sport hood" OPTION on the Barracuda (BH) or the Gran Coupe (BP).

Once the OPTION was released for BH & BP, the code starts to show up on the fender tags for 'Cuda (BS) models also.
(I'm NOT sure the use of the code was CONSISTANT after that point at either plant "B" or "E")

The multiple use of codes in conjunction with SHAKER (N96) & AAR (N94) hoods only complicates the question & use/non-use of the code.