Value of my Guild

[Timmark7]

Hello from Colorado.
My name is Mike and I live in beautiful Colorado. I found this forum when I was researching the value of my Guild guitar.
I taught myself to play guitar when I was eleven years old back in the early 60's. I started my first band at 12 and played in my last band at 16. Actually my last band was a country western band that I played bass for when I was in college, but I don't really count that.
My first electric guitar was a '63 cream yellow Fender Esquire. My last electric guitar was a '65 white Fender Mustang. I wish now I would have kept them, but I was just a kid, and didn't know any better.
Any how, if anyone can help me in my quest to find out the value of my Guild, I sure would appreciate it. I think it was made in 1984, but not sure. The label on the inside says the model is a D-66 NT. The serial number is KD 100051. There is a type written line on the label that says it was co-designed by George Gruhn. I have been to the Guild Guitar website and have found information on the D-66, but not have not found corresponding serial numbers. And what does the NT stand for? I paid $300.00 for the guitar about ten years ago. It is in excellant condition.
So, please, if anybody can help me, thanks in advance. I look forward to spending a lot of time on this forum.

Mike.