benjamin trail np2 suppressor replacement

Has anyone replaced there suppressor on a benjamin trail np2?

Iam in Texas and would replacing it come under the Alphabet org $200 tax stamp?

Just looking to see if I can fit somthing a little better to my np2

Just curious to see, iam from the uk and not having a suppressor on a rifle or air rifle is considered bad manners. And over the pond there is no tax stamp or forms to fill in and you can buy a suppressor over the counter.