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The H&R Trapper Model is a direct derivative of the H&R Model 1906 and was first catalogued circa 1924. It was serial numbered in the same series as its parent (M1906), so any dating will be an educated guesstimate. Yours should have the Gold plated front sight blade and from serial numbers I've seen - it probably was made in the 1926-27 range.
I have one catalogue listing, undated but must be from close to beginning of production that lists them at $7.50 (check pic below), while the higher end H&Rs were selling at that time in the $20 and up range.
Value will depend upon physical and mechanical condition.
Best value for a 100%/NIB piece is in the $350+ range (they are out there); down to arund $100-$120 for one in 60% FAIR condition.