I wouldn't put much weight on "SS vs. USS". The Enterprise herself was called "starship" much more often than she was called "United Starship"; the abbreviations SS and USS could be equally interchangeable.
I'd also leave open the possibility that the TOS style "multi-fleet" variety in signage already existed at the time the Kelvin was lost. After all, we only saw that single starship from that era, which means we have no proof other ships or fleets of the era didn't have their own distinct insignia.
Timo Saloniemi
I'd also leave open the possibility that the TOS style "multi-fleet" variety in signage already existed at the time the Kelvin was lost. After all, we only saw that single starship from that era, which means we have no proof other ships or fleets of the era didn't have their own distinct insignia.
Timo Saloniemi