Most likely this piece was shipped to a police department during WWII. A factory letter will answer this. Given the plating some of the finer markings may be concealed. My guess is that it was personal property brought in theater and for whatever reasons "found on post-returned to military control". According to Charles Pate's book on WWII military handguns the "big wigs" to include Eisenhower, Patton etc. carried Detective Specials.
No doubt your Dad acquired and retained the piece under irrregular circumstances. Victory snubs unaltered have crept at or above $1,000. In this state I'd hazard half that, but as you indicate, its going nowhere. In the same vein I would preserve it in the condition received. Its greatest value is as a treasured family heirloom.