Dixie Gun Works sells these warning that minor fitting may be necessary. Ours fit Uberti and ASM Armies without any modification. The rig is fired with the support hand under the grip/frame and behind the cylinder gap for obvious reasons. It's a steady hold with the downside being the fuzzy sight picture resulting from having the sight notch closer to the eye.
Colt addressed this on some revolvers by mounting the rear sight on the barrel.
The stock is mounted by placing the brass fitting down over the extended screw/studs on the army and 61 navy frames, aligning the hook with the cut in the butt of the revolver and tightening.
I found marginal improvement over my one-handed shooting and would imagine that stockless, two handed shooting would be more accurate because of the clearer sight picture at arm's length. The stock would be an advantage to the less-practiced handgun shot or on revolvers with heavy trigger pulls.