Welcome to the Forum...and yes, a "vintage" pair of aftermarket grips from that era....a look on the inside of the grip panels may tell you more, maker ??, or if converted from Colt use, etc.....
have seen the exact same grips from time to time back in the old days...NICE gun by the way. I do want to point out the cylinder is a later, non firing pin groove, like the "old models" usually come with, and obviously the gun has been "safety update" ( new lockwork with the transfer bar)
Did you check to see if in fact, the cylinder ,"may" be a early non marked 22 magnum?? those too did not have or use a firing pin groove around the rear of the cylinder, across the mouths of the chambers. We've seen folks from time to time put one of the mag cylinders, in early guns, "because they could"....the 22 magnum caliber was not developed until 1959, and there was a change to the bore diameter from .222 to .224" and if your gun is a 1958 should have the smaller bore barrel. Never hurts to check things out properly...over the years folks have done LOTS and LOTS to old revolvers.
as for the wood, most likely it is walnut..........BUT they made grips out of any and all types of lumber.
Again, NICE gun, enjoy it..........
