Use any Ruger grip frame you like, they all interchange with the cylinder frames.
Here is a 50th Blackhawk that came with a steel XR3, these grip frames are thinner and smallish, especially to bigger paws.
So I changed it out to a Brass Hunter, which is a Super Blackhawk "Size", but with a rounded trigger guard. Thus you don't have the Square back of the Dragoon trigger guard to smack your knuckle.
View attachment 54284
This 45/45ACP had the same XR3, again I don't care for it so went with the Birdshead, kinda backwards of what your wanting but showing you,,, The
do what you like options.
Now with all that said there is a difference in the Heights of the Early -vs- Current Cylinder Frames, when that happened??? I'm not sure,, but it's a small hurdle.
A take off Ruger Gripframe will get close to fitting gun/gun but most likely will need some adjusting.
example: My Birdshead above came off a gun like yours.
Finally, RW Gripframes makes some really neat and unusual, very high quality, and fit up even better than a Ruger/ Ruger.
But you can get some really neat custom stuff. NDIH, just have used some of Ronnie's stuff and it is superb.
Here is a Brass #5 Keith on a Single Seven 327M. Originally a Blued Steel Bisley, neat & nice BUT I always wanted a Keith#5 and with
RW making them in Brass it's Really cool, and this gun shoots.