I was noticing that the two famous droids from Star Wars, C3POC-3PO and R2D2R2-D2 have a four character alphanumeric name. Now, these are just two of so many droids out there, but I was wondering, in the Star Wars universe - do all droids have a four character alphanumeric name? If not, does the length or having an alphanumeric name as opposed to purely digits or characters have any significance?