The are paints that look a lot like Galvi. What is "bating"?
I don't mess with the upper end tubes, but there was something in the 753, or 853 about not coating them due to hydrogen embritlement. It might have been chrome since there can't have been much demand for galvi. Still, could be similar issues. Even with the chrome there were some makers who coated it anyway, and came out ok.
Galvi is applied in a number of ways with electricity, hot did, and thermal diffusion. There could be issues with any of these. The acids used, the levels of heat... Try the company.