if the L/S arrives in the cockpit with the incorrect a/c regn on it then any traffic officer worth his/her sort
A/ should have noticed that first
B/ get the load sheet re-done PDQ for the crew - if the Skip then elects to do a manual L/S then the T/O needs to get a copy from him for the file on shore
to LMC major changes like that is not very professional in my experience - if we had an a/c swap last minute then a new L/S was always done