The buyer is responsible for sales tax. And remember that the BATF is part of the Internal Revenue Service. And that the LGS can only get his/her FFL from the BATF.
But should you decide not to pay, it would not be the FFL holder who has to deal with it.
"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
Life Member NRA
Life Member NAHC
Former President of the ECPT (Eifel Combat Pistol Team)