That is Remington factory engraving. Model 10A Trap grade. Joseph Loy was their head engraver at the time but I don't know if he actually engraved that gun. Loy probably designed the pattern.
I have always thought that the Remington factory engraving of that period was quite good and this particular pattern is well conceived. It gives maximum visual impact for the minimum of work.
the reason that I am asking is a guy contacted me wanting me to engrave that pattern on this gun.
I am not really interested in doing the job.
is anyone on the forum interested?
The Remington website calls it nickel Teflon finish. Chemicals might not do the trick removing it.
My guess is that's a probably a pretty cheap finish though, so it will probably easily come off. None of the "production" gun makers do anything that's terribly complicated to finish a firearm.