I've actually had maple syrup go moldy on me before. So if the syrup is coming from a jug that's been open for a while, it wouldn't hurt to sterilize it.
That said, it seems to me like a waste of money since I seriously doubt that that little amount will have any noticeable affect on the flavor.
I have a friend of a friend who taps maples for sap to boil for their own syrup. I'm thinking of seeing if I could acquire some sap, enough for mash and sparge, and use that instead of water in a batch.
I read in a Papazian book that it adds a subtle "woody" flavor.