They don't issue export plates for motorcycles anymore. At least in my case, they didn't.
I am currently waiting for my 2002 R1150GS to arrive in Salalah from Dubai. They just issued an export certificate and sent me on my way. My company arranged for transportation of the bike to Salalah by trailer. Once it gets here, and assuming I complete all the formalities, I will let you know.
XTZ 750 '96