Found these rims in the attic..any way to identify the year??

Howdy all, cosgig here. So, I was working for a customer at a house he just bought from an elderly couple, and yesterday he has this pile of rims sitting by the attic door. I ask him if they came from the attic and he said yes, and that I could have them if I wanted!! I snagged them up and brought them home and have cleaned one of them up.

I know they're E-T mags because there was one center in a bag with some lugnuts, but I would more like to find out what vintage they are. I am considering using them on my 67 GTX for a nostalgic look, and was hoping they would be close to that year!! They are 15x7" and are uni-lug. They also came with 17 out of 20 lugnuts if they would help identify them!!

So, is there any way to identify the year of these?? Maybe by the center?? I'm lookin' to the experts... namely y'all fer help!! Thanks for any input received, Geof