I'm not really sure where to post this but I ran across this tag today while stripping my Passenger side front bucket seat apart to get ready for new buns & covers. This were original 69 trim 712 Black Comfortwieve seats. I had them recovered back in about 81 but the guy never removed the original Burlap as this tag was in between the layers of Burlap..
The original rear seat cover was dated 2/3/69 I thought I took a picture of the date stamp, but now I cant find it although you can kind of see the imprint from it on the rear seat bun. I will retake one and post it soon..
Here is the rear lower seat before & during tear down..