In a competition, the judges don't know what is in the recipe unless you tell them. If you tell them there's oak, they will "look" for that. If you don't they won't. If the oak is strong enough for them to identify without prompting, then you should tell them. If it is not too evident, perhaps just enough to add some complexity, it may be better not to tell them.
Sometimes some oak flavor will present itself as somewhat drying, which is probably not to your advantage in that style of beer in its pure form.
Long story short, I think you'd probably do better declaring oak.