Hi, not a pseudo mark but a hallmark.
Perhaps Austria, domestic silver hallmark, used 1922-2001, silver 4th standard (800), the head of a toucan facing left, in a hexagon. Under the toucan's beak the regional assay office letter G for the city of Graz. The maker's mark MG, unknown to me.
C left and 4 right, the shape of the mark and barely recognizable, what is supposed to be lions head,looks like Austria- Hungary Empire silver mark used 1872-1922.
Letter C is Prague assay office and number 4 indicates .750 fineness. The mark was used for small objects.
Prague silversmiths are not well documented, and I cannot even guess who the maker was.
Regards
Thank you so much for pointing me in the right direction!
I've just looked through all Austro-Hungarian hallmarks here and the shape on the earrings looks like the lion head hallmark (though I would never have thought it's a lion!). Also, the shape of the mark is a long straight line on one side, also more similar to the lion head hallmark.