Hope you don't take this the wrong way, sir.
If we go by the book, what you plan to do is illegal. The amnesty is for existing loose firearms with their original serial numbers intact. Technically, what you plan to do is "manufacture" a new firearm and use the amnesty to get the serial number into the FED books.I suggest you don't discuss your plans in a public forum such as this especially now that our ownership laws are under fire.
Please refer to item #1. I'm not a mod here but I enjoy our forum here on Glocktalk and would like to keep BOG alive.