I received 2 iPhone 4's. One from Apple and one from ATT. They have different numbers on the description line (Both are 32GB Black):
MC610LL/A AT&T
MC319LL/A Apple
I received 2 iPhone 4's. One from Apple and one from ATT. They have different numbers on the description line (Both are 32GB Black):
MC610LL/A AT&T
MC319LL/A Apple
I think you're right about it identifying where it was sold, but in the Settings app, it lists one of those numbers as a Model Number. (We can debate whether it ought to be called a model number, but that's what it is by Apple's standard.)
When it is being sent to a carrier like att or verizon the part number identifies who ts being sent to , for example
Apple iPhone 5 16GB White AT&T MD635LL/A
Apple iPhone 5 16GB White Verizon MD655LL/A
Apple iPhone 5 16GB White Sprint MD657LL/A
Apple iPhone 5 16GB White GSM Officially Unlocked MD294LL/A
----------
I have a break down of all models prior to 5, if u want i can email it.