GTs58
I'm the Wiz, and nobody beats me!
Appears some of the components have been changed and the front hub flange doesn't match the rear hub flange. The cable guides and locations might be a good indication of the time period along with the twin stik shifters. Here's a 1980 Le Tour, although I can't read the serial.
https://www.flickr.com/photos/27479638@N05/sets/72157605520575572/
https://www.flickr.com/photos/27479638@N05/sets/72157605520575572/