Do Identical Items Have the Same Serial #?

After doing a search, on About and Wikipedia, I couldn't tell if identical items have the same serial number or not.

Like lets say I buy two of the same 360 controllers. Do they have the same serial numbers? Or is a serial number unique to each copy of a unit?

Serial numbers are unique to individual items, where as model identifiers for identical items are the same.

If they are not unique, they ain't serial numbers but model numbers probably.

This just seems weird....who are you trying to rip off?

Well if you buy two Macbook Pro 13's with a 2.4ghz processor, 500gb hd and 4gb of RAM, they are going to have different serial numbers. Yes, they are the same machine built by the same company with the same specs, but each unit is an individual unit with its own identity.

Try doing that with firearms, and you'll find yourself in Federal prison. I have heard of consecutively serialized releases of identical custom items ie: #6/100 or serial number 06100US for example. Personally, I always thought the point of serial numbers was to distinguish between identical items that are produced en masse.