Newer C902s dont need unlocking?

hey guys just got my new Sony Ericsson C902 (on vodafone). Since i already have a phone which is good enough, i thought i'd unlock it and use another SIM card in it. After looking at many websites i thought i'd reflash the phone. but then i thought i'd be cheeky and just ask vodafone for an unlock code. So thats what i did. however when i told the lady on the phone my IMEI no and the model of the phone, she told me that the phone did not need unlocking and that vodafone haven't bothered putting any sort of operator lock on these phones.

So i thought i'd try my t-mobile SIM...and hey presto it worked! SO just a quick word of advice, just try and put your alternate SIM into the phone and see what you get, before attempting any sort of flash.