R.J.
They sound like the decorative part that would go onto pins stuck into a ball. Modern times; a styrofoam ball... older; a ball made out of rags or straw. Both are covered with fabric and then stuck through with pins to make home made christmas ornaments. We have several dozen my great grandmother made. GORGEOUS.
The indent is for the head of a plain pin. The pin head would be glued on or soldered on depending on the material. Typically one would bead some pins, and decorate the ends of others (with the pin caps; painting them or gluing on thread, usually to match or contrast with the ornament, or to look like pearl or mother of pearl), and then they were stuck on in rows to hide the seams of the fabric ovals/ make it more decorative. Similar to how leather furniture seams used to be "studded" with hobnails. The ornaments were usually quite ornate. Fabric scraps were saved from dressmaking, suitmaking, curtain making, and the bits that were especially "pretty" (satins, silks, damask, etc.) instead of being repurposed for quilts were repurposed for ornaments.
Like these
http://www.ornamentz.com/Christmas-Ornaments-Gallery-1.htm