After the awb sunsets and if we have a small window of opportunity I have a build in mind. I would like to build(or have built) a pmkms with the functioning folder, barrel threads and bayo. lug. Will I have to purchase my reciever after the sunset to make it legal or can I get the reciever now and not build it 'till after the sunset? It'd be nice to gather all the parts and wait to assemble them, but something tells me that the serial# on the reciever will tell the date and therefore decide it's legal status. Thanks for any help.