Lost my iphone 4 phoned police they need IMEI number?

Hi, i lost my iphone 4, phoned the nearest cop shop, they asked for IMEI, I gave them it, then i've just remembered does the phone not need to be opened to get IMEI? My phone had no battery left and had a pass code so surely they couldnt have the imei number, thing is i topped up that very night so the text i sent yhrough imessage from my girlfriends phone would have "delivered" as the 3g would have been on, would i be able to go in to police station and look at the lost property cause i could idendify my phone easily?

You don't have to open your phone to get the imei. Just type in *#06#. They may have wanted the imei because they can use it to make the handset unusable. It's unlikely they wanted it so that they could check all of the handsets in their lost property.

It would be a good idea to call AT&T because when i bought my Phone (AT&T Store) they wrote down my serial number and IMEI number so my guess is if anyone tries to reactivate the phone AT&T would have those serial numbers on file.

For myself, I have installed anti-thief app onto my phone. It will be helpful if my device gets lost, which will send me the SMS, web history, and even social network activities if the people who pick up the phone use my device to contact others. Check it out http://www.spy-mobile-phone.com/