GaMoparMan, you are absolutely correct...now that I take a closer look at my own photo, I realize that it clearly cannot be any code numerically higher than J51, since J52 is right next to it.
Blowing up the photo without question shows the suspect code as G54...which makes sense as the car still has the driver side remote racing/rallye mirror.
The good news is my Duster 360 4-speed is in the bodywork phase and should have new paint & stripes applied by spring.
I bought a mint lightweight Feather Duster hood (and a mint Feather Duster deck lid, too!) for it that will be scoopless and body only color...was going to hang the blackout & scooped hood on my garage wall as Mopar decor, but since it is obviously not original, I will just sell the scoops to someone who can use them for their car and get rid of the hood.