Don’t think Green Door was ever considered a Country tune. It was indeed a huge pop hit in 1956.WRR lasted a long time with 'Slow Jim Lowe' who had a country hit in the 1950s called Behind The Green Door.
Did Jim Lowe ever work at WRR? He was an air personality at a number of stations.
Jim Lowe - Wikipedia
I recall in the 1970s 1310 WRR’s music was a bit all over the place.Their MOR format was made unique with their "Library of Laffs" at 45 minutes past every hour. I heard George Carlin for the first time on WRR 1310, my Dad's favorite station at the time. By about 1972 I think, you were hearing things like Riders On The Storm by The Doors and Knocking On Heaven's Door by Bob Dylan amid the Frank Sinatra and such. In the final years they went talk but stopped that and I think were a combination of talk and music but by then it was beautiful music (at night, anyway).
The station dropped music in 1975 and became a full time affiliate of NBC’s News and Information Service (NIS) but I can’t remember if it stayed with the network until its demise two years later. There was a talk format between NIS and the sale and flip to KAAM early in 1978. I seem to recall WRR even had the short-lived national version of Herb Jepko’s Nitecap phone-in show, which was on the Mutual network…or is that a false memory?
BTW WRR wasn’t the only NIS affiliate in DFW. KRXV 1540 in Fort Worth also carried the network for about a year in 1976-77.