That's definitely what the "MY" means. With Holden these days, instead of two yearly facelifts, they are tending to keep the same basic appearance of each model much longer, but altering the specifications substantially as time goes by.
If you compared a MY07 VE to a MY10 VE, you would find that the specifications had changed substantially. With each "MY", the motor trade is able to track the relative age and specification of the particular car, whereas in the past, you would have had to specifiy that your VZ was a 2004, 5 or 6 model, and there would even have been differences between an early and a late 2005 model, for example.
I guess it makes things simpler for the factory, dealers, spare parts departments and the used car trade to differentiate between the versions of the same basic model over the life of that model.