Hmm. Period authentic. Hard to say unless you have a CSX car to compare it to.
Call Mike Mack and ask him, he has both. He'll be honest with you.
No pinholes, no panel mismatch, no seams, very uniform in thickness. No mismatched curves with the hood / etc. It's 3" wider in the buns than an FFR. And along with more "junk" in the trunk (the 3" wider butt), it's not perky.