What can anyone tell me about a Auburn Model 680SED?

Hello This car is a 1929 Auburn Model 6-80 3 window sedan 6cyl. Randy Ema

Helping a friend out. He's got a bunch of cars on his family farm. One is a shell, but has a plate on the side with the following information:

Auburn

Model Number 680SED
Serial Number 2986783
Engine Number 12990


Can anyone tell me anything about this? What year, what model, etc.? Or a place I can find info?

Thanks
<a href="mailto:[email protected]][email protected][/url]