Said Sheldon:

"The major difference between pre-1997 Dura-Ace and the rest of the Shimano lines is the cable travel of the rear derailer. Old Dura-Ace used a shorter amount of cable travel per shift. This has to do with the geometry of the cable attachment. Since the cable moved a shorter distance per shift, effects of cable friction or inaccurate cable adjustment were magnified."

Not to worry, though; any 9-speed Shimano shifter will work with any 9-speed Shimano cassette.

See compatibility chart:

http://sheldonbrown.com/dura-ace.html