Hopefully someone knows the answer to this or can point me in the right direction.

If an FFL Type 07 purchases a complete post-ban lower, than seperately purchases the parts and/or complete upper and sells as a complete post-ban weapon, would the FFL have to pay the Federal Excise Tax for manufacturing a firearm?

The ATF book on this is a little unclear and confusing.  Any help would be appreciated.

THANKS

If the 07 purchases a stripped lower, and builds it into a complete firearm, they are considered to have 'assembled' and must pay excise tax on the complete firearm.

There are some gray areas, though - if an 07 receives a customer's parts kit and lower, and assembles it purely as a gunsmithing service, they've still 'assembled', but to do they owe excise tax on the complete firearm, since none of the parts belonged to them, and they performed nothing but labor services on the customer's firearm?