It's not a license, it's a tax stamp. It is a tax on one silencer. You want another silencer, you need another tax stamp, so you need to pay another 200 bucks.
Meddle not in the affairs of dragons, for thou art crunchy, and taste good with catsup - George of Lod, Year of Our Lord 297
I always take precautions.
Beware the Evil Bullet Fairies.