Corn Pop -- oh, boy, what an un-realistic tall tale. I'll believe ol' Barry was born in Hawaii before I'll ever believe Corn Pop ever existed.
In California, if one removes metal from a hunk of aluminum and somehow there's an AR receiver lurking among the pile of shavings, one must apply to the state DOJ for a DOJ assigned serial number*.
*Used to be able to use a serial number of one's choice, but Sacramento realized it didn't have control of the process, the power to dictate a number, and was missing a tax source.