That's something you'd have to call and ask about. And you'd need to ask if they do in fact have the actual text messages and with a court order, can they be obtained.
I know that in recent court cases in (in the news), the last couple of years, lawyers have been about to get text message content, but have no idea which carriers were involved, or what the time fame was that the text messages kept that the lawyers got ahold of. (thinking back it was a matter of a couple of months if that long).
Ah found it...
http://www.msnbc.msn.com/id/5151987/from/RL.1/