Had an odd bug with renaming the Ambassador class I just got. (bugged this in game, but the bug report disappeared)
When I redeemed it, and renamed it, my main Prommy was my active ship. At which point the in-game model for my current ship (both in space and in the ship customiser) now shows the name I selected for my Ambassador. The UI and all the other details still match my ships proper name, it's just the in-game model that has its name decal wrong.