I think my pipe most resembles the A-8291-B which is second from the top.
To my eye it looks more like the top one. But then, you're a lot closer to it than i am.
I believe the dates shown correspond to the three generators used on the model A - Powerhouse (top), "long nose" (second) and "short nose" (third).
Your generator is a short nose. If your car is a 1928 model, it probably had the Powerhouse generator originally.