Never thought of that, I wonder will that include the rank at the cut off date for those that qualified on that date, their current rank if still serving, rank on leaving if they have left, or simply be bereft of any markings as some other medals are..
Taking the last point first, issuing a long service medal unnamed would be a departure from established practice. Long service medals date back to the reign of William IV, and have also been issued named to the recipient. In general terms, long service medals are always named, as well as campaign medals (with a few exceptions, notably those awarded for service in WW2). Coronation and Jubilee Medals are always issued unnamed, with the exception of the 1953 Coronation Medals awarded to members of the successful Everest expedition that year. Other than the Victoria Cross, officers gallantry awards were not named, whereas those issued to other ranks always were. Now that crosses are awarded to all ranks I assume that they are still unnamed, although I am not certain on that point. This all refers to British medals, recipients of UN and NATO medals, etc, will already know that these are not named, as is common with most foreign awards.
Taking Ian's point, medals should show the rank of the recipient at the time of qualification for the award. Innsworth's inability to recognise ranks which were existence at the time he was serving in Cyprus is an error, plain and simple.
One correction, as has already been pointed out, the naming is not "engraved" but impressed, using a machine with a collar which fits around the medal.