OK,

Filled out my ATF Form 5320.1.

Filled out my ATF Form 5330.20.

Ordered my fingerprint card(s) - FBI FD-258LE from the ATF website.

I see the address:

National Firearms Act Branch
Bureau of Alcohol, Tobacco, Firearms and Explosives
Washington, DC 20226

Is there a street address or PO box or something?

Mike