I'm new to the board and appreciate the exhaustive amount of research and time putting together this website. After looking through some Birmingham marks my eyes started crossing and I realized I'd be better off asking some experts. I purchased a salt, pepper and small sugar (?) bowl from a local coin shop. All three are sterling silver with cobalt blue glass inside, though the sugar bowl has a replacement EPNS spoon.
I want to narrow this down to just one item-- the salt shaker. The top of it has a different set of marks than the body, as shown below.
Expert help is appreciated! I wondered if anyone can identify the shown salt shaker. I'm mostly interested in when it was made and who made it. The entire set, other than the replacement spoon, has the mark G & A possibly (C & A ) on it.
Here are the marks on the base of the shaker..

Here are the marks on the removable top.

As required for posting in the FAQ, here is the full on salt shaker with it's cousin Pepper.

I really appreciate any help!
-David in Ben Lomond, CA