I looked briefly but didn't see your "parts wanted" post.
Can you post a photo from the web of exactly what you need? I have a 66 Dart rear lamp assembly I bought on ebay years ago & doesn't fit my 65 Dart. Chrome is nice. I don't know if same as for a GT and not going to research, you would need to do that.
My want ad is on page 4, under parts wanted. I actually fixed the tail light housing with J B Weld, and I got a replacement bulb holder cup, as the old one was cracked. It was the LH fender light assy. Thanks for your response..