When you say "Bead Blast" keep in mind that can be kind of a generic term.... Depending on exactly what the blasting media is. Glass, polymer, walnut shells, carbide, aluminum oxide, etc.
When I Cerakote I blast with 120grit Aluminum Oxide (per Cerakote specs) and it removes all previous finish, including most surface rust. The finish then looks a lot like the Stainless finish you get on some guns when new.
If your gun is Steel, and it is blasted then SOMETHING must be applied to "seal" the surfaces, otherwise rust is almost certain. Good luck!
CERAKOTE: Class 01 FFL