Another consideration with gun parts is it's material. I wonder why it snapped and just didn't bend. Even being casehardend it should have bent. I would anneal it before welding. That can be done in your oven on the clean cycle. If you don't you may end up with a big blob of porosity at the weld zone. Hopefully they didn't use cast iron for that part. That will make things really tricky. I agree that someone that works on guns and welds would be a better choice for the repair. There is functional welding and restoration welding and the corner shop may just weld it for function. I also weld for a living and wouldn't let many of the guys I work with get anywhere near my guns with a welding rig.
