Good Morning Everyone,
I have a Guild guitar I am trying to sell. Someone has asked me what year it was made and I have no idea. I was hoping maybe someone here can help me out.

The label inside the guitar says:
Model D4-12 NT HR
SERIAL AD421049–also stamped on the back of the neck.
MADE IN U.S.A.
GUILD MUSIC, WESTERLY, RI 02891

I’ve looked at a couple websites on dating the Guild guitar and I couldn’t find my serial number—or maybe I just wasn’t reading it right. I can post a picture or two if needed.

Thank you in advance for your time and any help anyone might be able to offer.