"C4" suspension code on my fender tag

That's a different plant than mine, so that may explain the difference. We have two broadcast sheets, fender tag, original owner's manual with origina sale info. We bought it from the second owner so we just have word of mouth on when and how he bought it, but we have his original California registration.

Do you know if yours had the grille medallion originally?
Yes it is a factory center grille insert car. I have the original grille with broken areas and it had the factory paint scheme so I used it to paint a replacement grille