In theory yes - but in practice it's probably best to post the names of all defeated armies/navies, so there's no doubt and also so that other players know not to attack them.
In the current incident I believe the ship in question had no move but was still attacked by mistake.
EDIT: as an additional comment, this works rather better over at TWC where there is a requirement to post screenshots. However I personally find that an unnecessary drag and would prefer to just post names if I were playing...
Bookmarks