Need server serials for 2 G4 Macs

Hi,

We just took delivery of two G4 Macs recently from a local college and they are both servers. Unfortunately they are password protected so we had a go at creating a new admin password so we could access the computer to see what software (if any) and hardware was on the machines. We tried this on one but it is now looking for a server serial? to set up the account, it's got the letters xsvr and a number of empty boxes after it where you need to fill in letters and numbers. If the college hasn't got this serial number, is there any other way to set up a new admin account on these computers?