Probably right. I think the S&W is 5-44, though they may have changed that on the newer guns.
I did a search on Heli-Coil. Small sizes available are: 1-8, 1-12, 1-14, 1-64, 2-8, 2-56, 2-64, 3-48, 3-56, 4-40, 4-48, 5-40, 6-32, 6-40, 8-32, 8-36............... Much smaller sizes than I would have ever thought they would make.