Iphone 4s, could it be still blocked?

Brought a phone from guntree, its sealed, haven't opened it, can i check the imei number on checkmend.com to view the status of the phone even though its not activated yet via itunes. Don't want to open the phones seal incase its blocked, as alternatively i could sell it to my mate abroad.

On billcrad you can find IMEI number if you don't want to open this.