What sort of markings does the wrench have? The logo is the best way to date antique tools since they were changed as the company evolved.
If yours has an oval logo on the open end, there are fairly distinct differences that should help you nail a date down.
I recently tried to estimate the approx year of mfg on some S-curve open end wrenches i found at a estate sale. The had no oval logo and only a W inside of a diamond on the shank. They were very early, before the oval logo was put on the tools, so pre 1919.
Take a second look at AA and use the logo table to get a better idea of what you have.
