That's what innokin checks. The correct response on their website is "This security code does not exist", which has confused at least one person: http://www.e-cigarette-forum.com/forum/new-members-forum/511258-innokin-security-code-question.html
If there was a clone going round with the same number you would see: "this security code has been used 3932 times"
The correct response is this code DOES exist if valid.