I would expect that to work, with the possible caveat that the device model and protocol (SIP/SCCP) would need to be identical.  Note I don't think this is going to work if you are trying to do a name change on one physical phone - the phone attempts to register using name 'SEP' using its hardware MAC, regardless of UCM configuration.  However in the use-case of a user replacing a broken deskphone with the same model, I would expect just changing the name to work.