Nope, actually what you saw was an optical illusion. I did have to go and take a look at the bullet. As it sets in the box at first glance it looks like its black on the very tip, but actually that is the sprue shear and its very smooth and shiny and the dark you see is a reflection of the beams above it . When I picked it up to see if it had black marker on it, it didn't, its just shiny like a mirror is all. Its a nose pour mold and that one happened to cut off very nicely.
Sam