Yes I think it is because we are spending a lot - sorry I can't say much but it's a lot. We've always had a 'google rep' and they rolled out the help line sometime this year to us. It's a 1800# and when we call it goes right to a person, no waiting. They do verify our account before giving us support. You can tell that the support is 'in house' and that it's googlers doing it, from the quality of the reps.
As others have said, spending a lot gets it. However, you should find an adwords manager ASAP as you would then have a point of contact if something goes wrong tomorrow.
I don't know exact numbers where they begin offering this feature, but I've seen a client on the $2k-3k a month AdWords budget receive phone support.