My understanding based on info posted in another thread is that you can get the $200 refunded if you haven't built the gun yet. Would that apply if you hadn't actually cut it down? I think @NWS had addressed this if I'm not mistaken.
Correct. Contact them and tell them you will not be building the NFA item and to cancel the stamp. They will void it and you should get a refund eventually. My last one took about 6 weeks.