@”Kapitán Denis” accent marks aren’t usually written, only in some special situations. If there’s need to differentiate kôd (code) from kod (at/by), sâm (alone) and sam (am, as in first person of to be). ^ is mark for long descending accent. You see there’s no accent mark on the more common word.
So no Serbs and Croats don’t write accent marks unless there can be some confusion or people are discussing grammar