I believe that is the code for the 71 15x7 rallye wheel. I know WG is for a 70, and I think WM is for a 72.
15x7 Chrome Wheel Application codes 7.0 Early 1970 (It was the size, App. codes were not used yet) WG Late 1970 WM 1971-1972 WP 1973-1977 Duane
Are there any differences in those wheels? Offset? appearance? How the wheels from the 1980's compare?