Sorry — no alien symbols.

Turns out they are hieratic numbers.  I’ve never had a class in hieratic (nor wanted to). It’s (crudely) like cursive hieroglyphs (if you’ve ever seen shorthand of English you get the idea). The numbers total 121 – the number of cubits of the shaft. No mystery (though I’m sure some will be manufactured).

Here’s an idea of what hieratic does to standard hieroglyphs: