The beads you show are European (German?) phenolics made for the African market, approx. 1930s onwards.

I do not know who did the decoration and would only be speculating to say perhaps added in Africa.....a nice touch though.

Here is a huge link.....though I searched "amber" I was actually hoping to find some on phenolic plastic beads, and there are some such posts there. Including a simple brine test and lots of images and discussion.

Suggesting to anyone to noodle around with the search feature.....we have years of discussions that are as interesting now as then.......