Looks like advanced oxidation/wear over a pretty good period of time. Font looks to be correct, oxidation appears over most of the body. Cap mounting area appears intact (about a .020" step on most distributors, you get the suggestion of that here). I have a known original 499 distributor with similar wear and markings to this.
Since he's seen so many of them over the years, Jerry MacNeish's opinion would be a good one to look for here -
Just my opinion -