Yes you are right it is not a rare occurence for example
we has a President dead now called Marquis de Charnace
while in fact it was Marquis de Girard de Charnace.
Apparently the sieur Girard who was married to a
Melle de Charnace obtained legally to add the name of
his wife because she was the last inheritor of the name
de Charnace to be able to continue the line.
So I am not saying it is impossible than de Bouillon be in
fact de Vere de Bouillon just that it is worth checking into it.