Not intended to upset your post. I was just confirming what you had posted about similar stitching and ostrich shell beads and the bushmen.
My pictures show no way ostrich shell. I am just learning about some of this stuff.

After you mentioned that I also looked for myself and I was glad to see that information as well showing on Pinterest a ostrich shell bead belt.

Unless Bushmen also used clam shell not related as evidenced by the pictures.

Thank you and have a great day
from Walter