Yes - it's a key to a great Templar's treasure... or to the Masonic one... I can't remember well
. Only the price - 260$ - is quite low for a such attraction
To be serious, there is no way it have any dual purpose. For me it's still imitation of very popular pattern used in 17th cent. daggers. Below you can see similiar one on pics from my museum - made in Italy at the beginning of the 17th cent., with openworked holes. Beautiful work which this one from ebay trying only to imitate by this points on the blade.
But if you want to search a creeping story in it, there is one, I heard or read somewhere, even don't rember where: in the openworked holes, there used to be a poison intended for a treacherous lovers. After the hit with a dagger the poison had to slowly kill ungrateful one....
Regards