S/N sticker question

I own a 50 year old 410 Mossberg (Model 183D-C) that was manufactured without a serial number. I received the serial number sticker that I am supposed to place on my shotgun but I have reservations about doing so since the gun is in near mint condition and I feel this will ruin it's character.

Am I allowed to have the government issued S/N engraved on the barrel instead of placing this eye-sore of a sticker on my gun? Thanks.