I'd wager this is the same tail panel paint as used on a 70 Cuda, and the hood stripes on a 70 RR/GTX, which was called organasol (sp?). You can get it in a rattle can from Totally Auto.
It is either Argent Silver 168Y13 OR Astrotone Silver 169Y16
Bottom row center Courtesy of Hamtramck Historicals
Not sure why Dart Dave was referring to Argent silver on a 70 tail panel unless he was thinking of the argent silver on a 69 GTX tail panel???
Thanks gents....the silver color is helpful as well...would the black be the one listed to the far right...Three tone black and gray no 846??
No, that is the spatter paint INSIDE the trunk.
For a 70 coronet R/T tail panel at least I am told a very close match to the factory color is John Deere Blitz Black. Low gloss. This paint is tough too. And it will save you some money. Good luck