You can download an administrator's manual here http://download.support.xerox.com/pub/docs/WC58XA/userdocs/any-os/en_GB/wc58xa_wc58xb_sag_en-us.pdf
also you can print a configuration page from the front panel that should have the count on it https://www.techwalla.com/articles/how-to-find-the-mac-address-on-my-xerox-workcentre