if so, when I expanded the photo, the white spots appear to be reflections off irregularities in the surfaces of the beads. I thought they might be fancy lamp beads, but I think it's just lamp reflections.

These beads tend to have manufacturing blebs and impressions, which show up as dark spots if the particular facet they're on is strongly reflecting the light. A real nuisance in daylight photos, because it makes the beads look far more rugged than they normally appear.

The marks could also be old-fashioned accession marks, which often featured a dab of white paint with inked numerals or letters.

I've emailed the woman who did the blog post, will see if she responds.