John, it would help if you could post the photo in its natural 186k format - the posted one is only 8k, and doesn't show much.
It appears it is a crossbar style boss, and would require a 2 arm puller, not a 3 arm. Usually you get both center parts with the puller, so you can assemble it with either two or three arms.
It also appears you may have a thread in the center of the crankshaft. If so you should put a bolt in it for the puller screw to bear on so the thread doesn't get ruined. The bolt needs to be long enough to allow the boss to come off the shaft for some distance before the boss hits the bolt head.
