Silver earrings bought in Brazil - maker's mark?

[smp330]

I purchased these from a weekend flea market in South Paulo in 2015. I only recently noticed the marks on the back. Does anyone know if it's a maker's mark?

[smp330]

flea market in South Paulo in 2015

That was supposed to be "Sao Paulo".... I also realize just because I bought these in Brazil doesn't mean they couldn't be from North America or Europe. I'm just not sure how else to find this information.

Thanks for any guidance,
Suzanne