Did someone pull a fast one on me?

I toured the Dell plant near Austin a few years back. They don't actually build computers. They assemble them with whichever parts they get. They don't keep extra parts on hand. Everything is delivered daily for the builds computers they are working on. They have several vendors and go with the one that can get the parts to them cheapest and quickest. When my school was deployed with Dell computers, we learned that, although they were the same model units, they were assembled with different components. Just depended on when the assembly took place, and which vendor supplied the part.