Similar purpose but the Wesson grip adapter is a three piece. It consisted of two panels that fit under the stocks with the third piece (rubber) that fit over the filler.
Last one I saw for sale was over $1000 and that was years ago.. They were only available prior to WW II. S&W made them for K frames too, I’ve seen a few on Outdoorsman’s.
You'd think it would be simple enough to manufacture. I wonder why no one did it after the patent expired.