I know what your thinking, it's plastic. It definitely isn't plastic though.
Okay, since it is real enamel, does that mean it's solid silver? It would be kind of strange if it wasn't?
I've got to add that the hand painting is a bit amateur, but it does seem to be part of it rather than being added later.
I cannot find any proper silver hallmarks. The marks shown seem to be makers marks only, CSG & Co.
What do you think?