As far as I can work out the D700 was replaced by the D800/D800E & the D3 was replaced by the D4. The D3s & D3x have yet to be replaced whilst the D600 was an "extra" added to the mix as a basic pro-sumer FX model. (Don't you just love it's "basic" features??)
The D300s has yet to be replaced as the pro DX body & there is serious doubt if it ever will be.
Second guessing Nikon camera releases is just as fruitless as trying to climb a mountain using a tooth-pick but all the same it is a topic that produces lots of discussion!
All the best Brian
If in doubt shoot it! There will never be a second chance.