To my knowledge, PetahW is exactly right. Twentyweights were only made in the "Dragon Black" finish with gold-filled engraving (though I've heard reports of a very few being made in the chocolate color) and they were not made until 1956 (maybe as early as late 1955). Too, to my knowledge, all Twentyweights had the word "Twentyweight" engraved on the receiver.
As an aside, I purchased my first Browning Double-Auto shotgun in Dayton, Ohio in the winter of 1961 (a gray-receivered Twelvette), just before I joined the USAF. As I recall, I paid $149.99 for it (new). Imo, in terms of handling and pointing, no finer repeating shotgun has ever been made. Val really validated his father's dna with this design.
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