Okay, I did find three or four chip faces (out of 12 chips, or 24 total faces) that had the round dots on the spots. It's clay, it's flush, it has uninterrupted crosshatching (similar to adjacent areas), and sorta off-color a bit. My guess is that it's from a hand tool (think blunt-end metal pencil or something similar) that was used to push the spot down into place when it lifted (during transport, or maybe between pressings).... basically poor workmanship, inattention to detail, or not knowing wtf the end-impact of what they were doing.
Many of the chips, spots, and even the edge machining/lathing sorta reflect speedy/careless/clueless construction in a similar fashion (along with the impurities/contamination issue on many chips), so I'm leaning more and more towards these chips being a low-volume non-production run probably slapped together by one of the bosses who either didn't really care, or didn't typically perform this type of work (you know, "leave the important stuff to the experts, and you should keep your ass in the office" deal).
With BCC, anything was possible. Home runs and horror stories abound.