Is my source for parts ahfoxparts.com, or are there other options likely to have 20ga ejectors I should check with?

The same friend who gave this to me has a machine shop and many years of gunsmithing experience. I would think what might be simpler than fitting new ejectors might be to drill a hole in each ejector where the pin used to be, make new pins of the right length and diameter, and press fit them into the ejectors.