I feel the final, production bike, will almost certainly be launched at EICMA (Milan) in November 2018...
I-F SA can get in on the 1st 'batch' of bikes, then likely April/May 2019.
(you must remember, that SA sources from a European Yamaha factory, not Yamaha Japan, and if Europe say needs 7,000 bikes opening order, and the factory produces say 5,000 units in the 1st 'run', then SA could be delayed to say a 2nd 'run'...I guess 3+ months later?
(this happened with the 660 Tenere, just as Operator says, whereby SA got product 12 months later).
Chris