From what I've found in newspaper articles and "Variety" blurbs, this was a syndicated/franchised show that debuted in 1949 and started out in Maryland, Pennsylvania, and Delaware. After the game was played on "The Garry Moore Show" by its cast in late 1953 (seemingly becoming a regular feature of the show for a time), "Shadow Stumpers" was snapped up by more stations. Some opted to use the format with different hosts, with a few even making it purely a call-in game. Altogether, the game was seen on 36 stations at its peak.

Baltimore dropped the series in mid-1955 with the rest canning their iterations by the end of '59, though in 1963 Fremantle of Canada got the exclusive license through a subsidiary agreement.

I say all that because this video is...really strange - it's clearly a pilot given the nondescript sponsors and lack of commercial breaks, but I'm not sure when it was done. It's likely not 1949 given that the opening spiel indicates the show's currently airing in Baltimore, and for the same reason it likely isn't connected to the Fremantle licensing. My best guess is 1953 or '54, as something to demonstrate to stations who were interested after seeing the format on Garry Moore's program.

This was a game show, families playing against each other- and the show wisely (I think) included even four-year-olds: "Buzz" in a little man's suit & fade hair cut, poor little "Buzz" Spatz, too bad he picked his nose almost the entire show. That little boy was very bright! It's wonderful that families really dressed up to be on Tv.