From what I read in the other forums this may be a generic email and not specifically saying you are qualified for the upgrade. The wording is very misleading and I believe only those who signed up on the Droid Does website are getting them. Not sure about that last part though. Even if you get one, I'd still call to be sure before getting your hopes up.
I spoke to someone at a Verizon store and even though I'm eligible in Nov, I have to wait till then - they won't offer me an early upgrade. Luckily I'm switching to a family plan and will be using my Dad's upgrade, hehe so I should still get mine early.