Top pic of the sprue hole with the Philips screw showing. See the ragged edge along the bottom? That's where the cone/round stone comes in. Just a couple twists to break the inside (?) edge, then stone it flat. I scored the top of a lot of molds before I figured out the burrs there can move around. Better to break that edge IME.That plate has been stoned flat. Its something I do with all Lee molds before I ever cast them. Heck, I wont even open a lee mold today!!! I unscrew it and run it on a flat India stone!!
Not sure what your seeing but maybe just the pic.