Server 2000 access license

I am rebuidling a server that currently has Windows 200 Server installed on it. I have the installation CDs but the guys before me misplaced the license key. My question is can I somehow find the license on the existing server that is running Server 2000? The end goal is to not have to purchase Server 2000 a second time. (We have 25 CALs to use with this server)