The only silver lining I could see, is that this old coot will botch his arguement and end up losing. Man, I know I'm grabbing at straws.
Break that straw with the little fact that the NRA lawyer apparently not knowing why they went to the Senate records of events regarding the legislation with which Metzenbaum was involved, and there could be real trouble here.
A visit to the thomas.loc.gov website and a little reading will reveal that the Courts look to the records of the various houses of Congress to help determine what it was the legislators intent with regards to the legislation in question.