A bead blaster will impart the color of the media to the part that is blasted. For example, white silica sand gives the brightest finish, reddish brown flint will give a brown tinted finish, black silicon carbide leaves a blackish tint, etc.

To keep from fingerprinting, wipe down with oily cloth, then a clean one.

The easy solution in this case might be to finish the frame the same as the slide.