Is this pretty straightforward or is a gunsmith actually necessary. I don't really want to mess it up and have a sloppy frame but if it's hard to screw up I'd give it a shot.
It's kind of relative to your level of mechanical inclination and metalworking experience/ability. Metal will need to be removed, precisely/equally from both sides of the slide, until it fits. This is easy for some, and impossibly difficult for Bubba. As a machinist, I'd attempt it without a second thought.