The authority on Gas Globe identification, history and value is the PCM e-book "Gas Pump Globes"
The 2020 edition says that the most common shell shaped milk glass globe with embossed "SHELL" lettering was used from 1931 to 1960.
It is possible that a non-visible curb pump still in use in the 1930s or later could have had that globe on top if it had a provision for a globe.

Jim "Oldgas" Potts
Your host and moderator