If the base and top are mismatched, and that seems a strong possibility in spite of the fact that they fit well, it throws this whole thing wide open, since opaque cut-to-clear was and continues to be widely made. Is that what is meant by putting the cass among the pigeons? I looked "cass" up in my dictionary, but it wasn't there.
The only thing I'm very confident of is that the style of cutting, not the punties but the lines, is not mid-19th C Bohemian. I think that without identifying a maker that used either the blank or the exact outer color it will be impossible to positively identify this, or even date it.