This sounds about right to me, my own example(same age as this one) had the same effect. Catch the angle right and the original stardust finish is viable, at other angles you'd never think it was there at all. Is harder to capture the finish in photos than viewing it in real life and is just down to surface scuffs from 50 years of honest wear and tear.
View attachment 711052
No original finish left in the above example surely? Wrong, in person the original sunburst finish is clearly disable all the way around the case. Very difficult to capture in photos.
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