My guesses:
- the 120-300 f2.8 SR announced yesterday was designed from scratch to AF optimally on both F and Z mout bodies. This is the only way such a strategic release would make sense and Nikon does make sense 99% of the time for such matters.
Yes i am sure you are right but i think that Nikon owners of a long pro tele simply will have to use the converter so it will work on either a D6 or a Z.
Usually these people have invested in D5 bodies and Nikon wants to sell them a D6.
Probably the latest long telelenses have been optimized for both Z and DSLR and might have an option to be converted to the Z-mount later on.
or maybe this 120-300 is the first.
(The D6 has to be very good to be able to compete against the Sony 9 markII; then what will Canon release?)