To be considered a pre-ban semi-auto assault rifle, the rifle HAD to be in a pre-ban configuration BEFORE the ban went into effect.
Thus my 1990 purchased AR15 qualifies, it had all the "evil" features before Sept. 1994. But my 1978 vintage 10/22 does not qualify because all I ever added to it at any time was a scope. So inessence, I have a 25 year old post-ban rifle. It would contrary to current law for me to now add more than ONE evil feature.
BATFE has stated it is up to the owner to provide proof of the rifles configuration before the ban.
Is a documented pre-ban 10/22 worth $400? That's up to you. I never felt the desire to alter my rifle when I had the chance, so I would never pay that much $$$ for one that was.
But that is me. You have to decide for yourself. And I won't hold how you spend your money against you.
After all, we are all in the same boat.
edited: Damn! I really should proof-read before I hit the "Submit" button.