"Name, rank and serial number" - why the serial number?

Really? :dubious: The “other ranks” did.

It does seem odd to say the least. However the past tense is the key. They do now, and have for the last 95 years.

I was going on my experience chasing down my two grandfather’s records from WW1. Until 1920 officers did not get a number. One grandfather was a sargent, and then commissioned on the field into another regiment. As a sargent he had a regimental number, as a captain he didn’t. Enlisted men’s number changed if they changed regiment. My other grandfather served in two different regiments, and had different number in each. Things are much more regular now.