Removing Jailbreak from 3gs????

[mossy600]

I bought an iphone about 10 days ago and I am taking it back as the battry is faulty, I have installed Jailbreak perviously and I updated the iphone to 3.1 hoping will get rid of the firmware and yet showing 3.1(7c144).
Can any body put me in right dirction? and would apple store care about that little thing?

[BertRoot]

Erm if you have updated and not rejailbroken then you are clear. An update of firmware removes the jailbreak.

[mossy600]

Erm if you have updated and not rejailbroken then you are clear. An update of firmware removes the jailbreak.

Thats what I thought but in About section, version is 3.1 (7c144), isn't that mean its been jailbroken?

[kracken]

7c144 is firmware version , it isn't jailbroken

[mossy600]

Thanks guys for a quick reply