Converting a RIA GI model to a Tactical model is a LOT of work, but it can be done. I did it to one of mine. I succeeded, but it was tough, the GI frame is different than the Tactical frame, and the beavertail requires a lot of steel to be removed. Getting it to fit cleanly and look right takes a lot of finesse and patience, and once you start you're committed.
Forget about having a gunsmith do it, you could buy two new Tacticals for what that would cost.
I strongly advise that if you want a Tactical, then buy a Tactical! The conversion cost me a lot, but I also had the pistol polished and blued. I also sent the slide to Novak and had them install their tritium night sights. Turned out beautiful, but a lot of $$$$$.
But AFA the GI sights, people have been using them for 100 years. Hammer bite is no fun though, I know all about that.....