Mike, the 311 I posted may be a 1931 model.
The serial number has the "P" suffix, which Jim Ross says is an indicator that the carb has the primer button at the base.
I am not certain if any of the 1930 models came with the "P" designation, I need to talk more to Jim and Sam Vance about it
Best,
Chris S
He's livin' in his own private Idaho..... I hope to go out quietly in my sleep, like my grand-dad did..... and not screaming, like the passengers in his car...