I know that some Remingtons have a three-letter barrel code, but that those only ran from '43 to '53 and given that the 878 wasn't made until later than that, and the code I have is three different letters, it's a bit of an odd duck as far as I can tell.
Anyway, the code I have is "ARP" followed by "35"
Here is a picture:

Any thoughts? Just trying to put a date on it is all. Thanks!