If you take the frame to a competent blaster, you won't encounter any damage. Someone would have to get "determined" to erode the metal of the frame with a media blaster. You could request they use glass bead if you're really concerned.
Or, if you want to, you could always strip it with chemicals. Aircraft Stripper does a very nice job without damage to the metal. You'll have some elbow grease in front of you, and afterwards use Green ScotchBrite pads to remove any final areas. Wipe down with Acetone afterwards, and prime and paint. Or powder coat, or...