Moved this thread to Gun Laws . . . you'll get more answers that way.
I can't address you're particular issue, but it's an interesting one (though any gun law issues are dangerous ones
The one thing I can contribute is that reading the C&R laws alone may be misleading, since original, full-auto, AK-47's could technically be considered C&R's . . . yet they're obviously not. The devil is in the details, and the details are the voluminous Federal Regulations and ATF enforcement policies.
Calling the authorities is a good idea, but won't protect you from other authorities. I'd want confirmation in writing.