Patent date should read "June 8, '97". The hole in the end of the handle is for a die holder. See lot No. 10 in the photo below from the 2010 Wrenching News Doug Busch Auction for a complete set in a wooden box. Lot 11 shows one without the die holder option.
(http://i222.photobucket.com/albums/dd3/buswrench/busch-2010/busch-008-20.jpg)