i am eligible for my last NE2 upgrade on 4/1, but have been able to upgrade at a discounted price on the VZW site for a couple of months now. since i'm not technically eligible for 14 more days Wirefly.com and Best Buy Mobile tell me that i'll have to pay full price, therefore VZW is my only avenue for purchasing this phone.
for this reason i have been on the VZW upgrades website every few hours since yesterday morning checking to see if this phone has popped up yet. i just now called 877-228-5774 to see if i could order early. the rep, Raymond, said he'd try to place the order now to see if it would go through. no dice. but he did say that he could place the order for me first thing tomorrow morning. Raymond gets into work at 4:55 am Mountain Time and leaves at 1:55. they staff that 877 customer service number 24/7, so if you wanted to phone in an order you could call in at midnight if you wanted to.
since Raymond was being so helpful I asked him what time the phone would be up on the website. he said they go up at midnight, but i didn't ask him what time zone's midnight he was specifically referring to. i'm sure they don't stagger the website's launch by region so the answer to your question is that three hour window between midnight Eastern Time and 3 am Eastern Time. sorry. i guess i could have asked him to be more specific, but i'm confident he actually would have known.