Our boat (same model, vintage 2001) has a separate breather "through-hull" right next to the fill cap. See attached photo - the small thing circled in red.
BTW on the opposite side, the arrangement is identical for the stern water tank - same breather hose + "through-hull" there.
While filling up, this breather annoyingly bursts easily a spoonful or two of diesel out when the tank becomes full - have developed quite good a t listening when the tank is approaching full
BR,
Tommi
s/y Anniina