Me so jelly!
Those appear to be the bulldog grips from the original .44 Bull Dog. Folks did not like them on the Bull Dog with its much heavier recoil and so they turned up in shops and at shows regularly. I put them on my Undercover in 1978 as it made it much easier to fire with greater accuracy when doing fast shooting. Notice it covers both the front and back of the frame and the originals did not so you were flesh on thin metal. The stock that came on the Undercovers were tiny and slick and the gun would squirm about when shooting The Bull dog grips are great and all you need.
I really like that three inch.
Thanks for posting it and sharing with us.
-kBob