Ethain
I think your car is a 1913. It is not a 1912 Model 34, as you can see from Marks car the Model 34 had full eliptic spring on the back, where as yours has 3/4 eliptic. Also the Model 34 had external to the body gear lever and hand brake, where as yours has the internal levers.
It is not a 1912 Model 36 as it also had external gear and brake levers, and the headlamp braket was on the outside of the frame where as yours is on the inside of the frame.
Yours is not a 1914 B24 as in 1914 the stearing arm ran down the same side of the frame as the stearing wheel. Yours crosses to the opposite side. Which was the case in the 1913 Model 24.
Buick did not use brass spring hangers, so your were cast in brass/bronze due to wear of the original hangers.
Here is a 1912 Model 36.