To answer,
No, it's in the BCM. <~~~~ this is total Bull Shit
I don't care what the hyperlink says on the other forum that's BS too, I know, I have swapped clusters in different Aleros and the cluster retained it's mileage removed from the other car.
It's stored in the cluster. If you want I have a cluster that reads 187,000 miles

you shouldnt be changing your cluster anyway the cluster is supposed to read how mnay miles are on the car NOT THE ENGINE!!!