I don’t have receipts for 50% of my firearms because they’re private sales.
The serial number on the firearm would prove date of manufacture.
By how that statement she made sounds, to me it seems as if you own an assault rifle now you can not sell it as purchasing or possessing would be illegal if you’re not grandfathered in (doesnt apply retroactively). Id love to read her proposed bill and see exactly what’s on it, but I imagine the committee Obama opointed to draft the bill will make modifications to it.