This is a follow-up to this question.
In short: I need to buy an iPhone 4S with iOS 7.0 (and this version specifically, not the latest 7.1).
I have mailed an Apple reseller asking if they had any in stock only to learn that Apple does not print any information about iOS version on the box so they cannot tell me. I thought if there were a way to identify what version of iOS is installed based on serial number or some other indicators I could ask resellers very specific questions (i.e. Have you got any XYZ series iPhones in stock?).
My questions are: is it possible to recognise the iOS version based on serial number or any other factor in a new iPhone? If yes, how do I do that?
To be more specific: I would like to identify a range of serial numbers of iPhone 4S that shipped with iOS 7.0 installed as the original system. Is that possible?