Transfering the MSH internals to another one is really a non issue. I thought that it would be as the m1911.org site "does not recommend" that you disassemble the MSH. I did only because I had to install a new one and transfer the internals. No biggie really.
I have a SS SA Mil-Spec that I just installed a flat (personal preference) S&A mag guide (model # A+GMFS) into. When I ordered it, per phone, I told them what I was installing it on, and for ten dollars more, they sent it with the proper spring and cap ,etc. already installed. That made it a no-brainer to install. Also, that made it possible to keep my old ILS housing intact ,in case I want to change back to original.
By the way, it fit perfectly with no filing necessary and the finish is very good quality and really matches the gun's finish.
Guess you can call me a happy customer of a Smith+Alexander product.
Now that Saddam is caught, does this mean I have to buy all new targets, and if so, who's next???