Thanks for posting this, they're really cool and I think I might have a tip to one. Will take a pic when I get home and post it to see what you think if you don't mind me doing so.
I have several burinated pieces but unfortunately I don't any pictures of any except for these Bifurcates with Burins on the bases. This actually a trait on these types of Bifurcate Points. Why they did it, I'm not really sure. I have never seen any definitive answers on that.