Where Y'at Bera, If your looking for Houge, I'd check to see if Houge even makes it for the early frame. Aren't those the rounded butt frame? Mine is a Post 151 Square butt frame. As a kid I always heard I had a Lead Butt. Now it's Square.
I tried posting a pic of mine but the file is too Big. Yeah, that's what she said.
You might want to ask here.http://rugerforum.net/ruger-double-action/
Love the screen name Abby. Dad said back in the day they had the hogue rubberized grip, but after the frame went squared, they disappeared.
So at one time it was made...
Where Y'at Bera, I'd see if the guys on the Ruger site have found a fix/alternative for the Houge grips. This may sound strange but how about tracing out your frame & a Square frame. Lay one over the other, cut out a template & make a small wooden spacer to fill the extra space in the grip. Mine took some fitting to get it right. Your might take a little more. It may be larger than the Round frame grip made for your gun but it would be Nice Houge grips on your Dads gun.
I bought some rubber grips for a Security-Six a few years ago at Jim's. I dont remember if they were Hogue grips, but they were very similiar. Big improvement over the stock wooden grips that were on the pistol. Maybe, they they still stock them.
I did and they only had the post 151s which also fit one of the current production ruger revolvers, but once again thank you for the heads up. We will get lucky sooner or latter and I appreciate you guys helping.