Upgrade of Mac Pro with iMac upgrade disk?

[Taxer]

I purchased an iMac last week that had Tiger installed but included the Leopard upgrade disk. I also own a Mac Pro running Tiger. I'd like to know whether I can use the upgrade disk that came with my new iMac on my Mac Pro instead. I'd seen a post somewhere saying that different Leopard upgrade disks are made for each Mac model and can't be used to upgrade the system on a different model. Is this true?

Thanks.

[mad jew]

Using the Leopard disc on the Mac Pro too would violate your EULA.