Wow. I think I’d have assumed that was expertly refinished.
Not casting any aspersions. There are plenty of firearms older than that Mars in similar “mint” condition.
There's only one person I know with the nous to do a restoration this good (see Airgun Collector issue 2) and I'm pretty sure it's not one of his creations.
Vintage Airguns Gallery
..Above link posted with permission from Gareth W-B In British slang an anorak is a person who has a very strong interest in niche subjects.