is there a Iphone 5.1 and an Iphone 5.2, ?

Is there a Iphone 5.1 and an Iphone 5.2, ? I read blog's and forums refereeing the iphone 5.2 is the GSM the international one and the Iphone 5.1 is the US based. Is this True And if it is true, is that mean that the unlocked iphone 5 is the 5.2 ? and the contract iphone 5 is the 5.1 ?

Pls need to know quickly .

Thank You