Ruger MKII, MKIII, 22/45, interchangeable frame?

[richyojimbo]

Hello
Was wondering if the barrels of ruger 22lr in pistol mark variation interchangeable. Will a markII barrel work with a 22/45 frame?
Or will a markIII 22/45 frame work with a markIII (steel frame) barrel?
Thanks!

[gunrun45]

The barrel itself will. I believe what your asking is if the upper receiver (serial # with barrel attached) will work between the models?