Hi,
One of your images was downloaded, cropped and resized, as well as contrast auto corrected, but this is the best I could do.
There IS Birmingham anchor mark (red arrow), but everything else is out of focus. What`s the year you mentioned based on?
I don`t think marks are faked. It`s rather well made (the setting of stones) but pearls are obviously glued.
In this type of pearl setting, every pearl has a hole and it`s carefully fixed to the protruding screw pin.
In cheaper settings the pearl is carefully and neatly glued. It`s possible pearls were glued later, genuine but unprofessionally repaired (glued). There is no doubt about it; pearls are not supposed to be fixed with so much excessive glue.
The color of gold does not tell much about the fineness, and besides, it can be easily tested.
In a word, better close up images of the marks are needed for any further search.
Best wishes