A horn sans lacquer Vs. a lacquered horn will change the perceived sound slightly (primarily to the player), especially in the way the horn resonates and the vibratory "feel" the horn has in the players hands. This doesn't really carry over too much regarding the way the horns sounds to the listener. Side by side, most listeners will have a hard time telling the difference.
Would I buy a horn that has honest, long term natural lacquere wear, yes.
Would I buy a new horn with a bare brass finish, quite possibly.
Would I suggest that you take your pre lacquered horn and have it uncecessarily stripped, absolutely not.