Nope, they aren't going to work. Different part #'s. You can look this up at
si.shimano.com, go to 'road', then 'Dura Ace' or 'Ultegra', then find the EV (exploded view) of the component you're looking for. The hoods (Shimano calls them 'bracket covers') are #12.
Dura Ace:
Dura Ace 9000 EV
Ultegra:
Ultegra 6800 EV