Coming from a ZFD 7 background I seems to be missing this in ZCM 10.3

In doing some imaging testing i've noticed that if I have a machine that tries to register the same name, it has it's name but with the GUID on the end of it, as we are using the serial# of the machine as the name of it in AD and ZCM, we'd like to keep the names just as the serial# and not with the GUID tacked onto the end

Is there some obscure little config flag I need to change in the zone config that can achieve this, as i'm yet to spot it in my zone or the docs