Not being sure what the Curtiss Sedan looked like I did a quick search and found a photo of one at Evergreen a few years back. I’m fairly certain it is the airframe now outside the museum.The rudder and wing attachment points have been removed but the other ID points seem correct though the step is hidden by one of the tyres. From the little info I could find it seems to have been put up for sale by the museum in 2013. It’s a real pity to see it languishing outdoors – hopefully this is only a temporary arrangement.

Photo on this website – http://www.rodbearden.com/Av09/Evergreen%20Aviation%20Museum/Curtiss%20Air%20Sedan%201.html