Jeff... without any tribal knowledge, my entire thought process would consist of something like this:
What color is the back?
Plain vibrant white is an immediate flag
Where are the porcelain chips, how do they look?
the chips appear to be placed intentionally. normal chipping near grommet holes are the result of a screw being torqued too tightly. those chips are obviously from blunt force multiple times.
How was this sign used?
As I mentioned before... not something I can 'imagine'
GOOGLE & OldGas Search?
what comes up in a quick search
More thorough search:
Books and literature, have you ever seen this sign?
Do all of that every time you come across a questionable sign and you will most likely come to the right result
