I've done it. I used a harbor freight gun and their black grit.
It leaves a very rough texture with micro "spurs" sticking up. I knock those off with maroon scotchbrite. With slow rust brown it comes out a thick mat rust kind of thing. It seems to help the solution bite quickly.
I do not see much difference between file, to 320, scothbrite, then rust.
I have not tried bead blasting. I it looks nice with modern blue. Maybe there are possibilities. It may obliterate some finishing marks with out making a rough surface??