I think the Birdshead grips are older designs, they are made in steel and stainless steel, don't have the locations for the locks.
Grips are getting harder to find as the old Ruger grip manufacturer went out of business some time ago, think they were named Lett's (SP?).
The black markarta (SP?) ones were available on Cheaper than Dirt a while ago and bought several at a really great price...
The easiest way to get one of these, if you want shooters is to locate the grip frames and either attach them on your own, or have a gunsmith fit them to your revolver.
That would likely be the easiest, especially if you want a shooter.