It happens more than you think, When I was in the South Central I had a guy running around posing, I also had reports last year of a guy in Palmer Park here in Washington claiming to be a DWCO and checking licenses. I went there several times in my personal vehicle and regular hunting clothes but was never approached by anyone.
Thats one of the reasons I always say contact a WCO or supervisor if you have an odd encounter.

BTW all WCO's/DWCO are required to have the PGC issued ID on them while working, in or out of uniform.

I dont know what or who the OP met with that day maybe an Officer from another agency?