I wouldn't worry about it if it shoots good and ejects/extracts fine, ever see a jeweled bolt? Consider it a custom finished chamber!
If it doesn't work right, return it to H&R, they'll fix it.
FWIW, I have a 44mag that I rechambered to 444 Marlin, it has some strange markings in the first 6-8" of the bore ahead of the chamber, it shoots excellent just like all my Handis.
Tim