Folks, this helmet in question is very common and typical in construction and style. Yes these were based on 16th century Spanish helmets of similar construction. As shown in the picture of the Maranao data warrior the had a section for a plume of flowers and vegetation which would make it even more "costume-ish" for American/European eyes. Remember though that in this region of the world flamboyance was not seen as a detriment. Similar flamboyance was seen all over Indonesia, at once time in Malaysia, as well as the Philippines. Variations in piercing and okir would be present, but the basic form would be the same.
I do agree that the ear flaps are on backwards. And by the way, the Maranaos were and are still known as great artisans in brass/bronze working. Some of this is still being made today in Marawi City in Maranao country.
This went for a steal - wish I had found it....
