Neither my pistols or my rifles are registered in any way
That's what you think (Ha, ha, ha) LOL, the FBI has all your information in their computers. Any time there is a transfer of firearm by a FFL a form 4473 has to be completed and transmitted to the "National Instant Chriminal Background Check System"
Along with all of your information and the serial number, manufacturer, model/make, type (rifle or pistol), date of purchase and purpose of purchase.
And yes you have to fill out a Form 4473 to buy a lower.