The 870s here run from early 50s to mid 90s, and all work fine.The oldest seems smoothest, but I think it's work polishing rather than better workmanship. Bet yours is smooth also.
One small thing, check and see if the bbl is marked for 2 3/4 shells only, or for either those or 3 inch. Don't use 3" shells in a short chambered bbl, it's not good for either you or the shotgun...