Okay. I've got a 3-screw Blackhawk made in 1969, with the aluminum XR-3 Red frame. Hate the balance and really dislike anything aluminum on a firearm. So I found a Stainless Steel XR-3 grip frame with a hammer and trigger. Was told by the seller it would fit my 3-screw. But even if the frame fits, what will I need to do to get everything else to work correctly? Is this going to be a real headache?