I doubt you can tell by just looking at the cone. Maybe in the leaf shape. Try smelling them. You could always send them off to a lab to have them test the alpha acids. But I doubt it would be worth it.
Just read some other stuff on identifying unknown hops and people also suggest making a tea with them. Although, unless you have some knowledge as to other variety tastes, you could still have trouble. Either way, you should be able to get an idea (citrus, earthy, spicy, etc.)