Quoted from Vintage-Pinball:Another favourite of mine. I can remember playing a freshly unboxed, brand new one at my local bowling alley! And the guy who did the job let me play a few credits that he put on for me
Your example looks pretty good for its age. Most of these have wear on the kick out holes and the purple diamond shapes between the pops are often worn away.
With your one, I'd carefully clean the cabinet and air-brush the worst sections and leave it at that to preserve its originality rather than go the whole hog.
If you're going to airbrush parts of it, it's going to look half restored.
I vote for repaint, but I usually do, unless the cab is in real good shape. Otherwise, leave it alone.