“I thought I got this at a wrestling convention in Duluth”

The Duluth reference here is likely intended to be Duluth, Ga., since the Chris Stevens character on Northern Exposure is a native of Wheeling, W.Va., and any wrestling convention he attended would probably have been during his years at Wheeling Central Catholic High School. (Assuming “convention” means “tournament” — it could also mean a gathering of popular wrestlers signing autographs or some other thing.) The distance from Wheeling is great in either direction, however — 650 miles to Duluth, Ga., and 950 miles to Duluth, Minn.