True.
There ARE some states that, not being satisfied with Federal Legislation, passed their own State Bans.
Of those few states, again, SOME allowed so called "grandfathered" "Assault Weapons" to be possessed if manufactured and or possessed prior to the state ban. You would need to do some research to find out just exactly what those bans entailed in each of those repressive states, as they DO differ in their approach. Some may indeed allow the acquisition of "pre-ban" weapons, and some have a cutoff date, after which no new ones may be acquired, regardless of "pre-ban" status.
Bottom line is that for SOME people in SOME of those states, a "pre-ban" rifle may still be legally acquired, thus retaining SOME of the "value" they held before the end of the Federal Ban.
Before getting involved in a transaction, on EITHER end, involving one of those states, be certain to thoroughly research the laws applicable. Preferrably by Government Publication, rather than The Internet.
Lonny