I think they got iPhone 4 first quarter 2010, no more than 6 months after release to AT&T.
http://en.m.wikipedia.org/wiki/IPhone_4
i have a diehard Verizon-only friend.
Some of these guys are as rabid as iPhone fan-boys!
I think first quarter 2011; the 4S came out in October, and that's when I switched. I am pretty sure, if my memory is correct, OG Droid came to Verizon in Fall 2009. A year later I got the DX (2010), then the iPhone 4S (Oct 2011), and now the 5.