Bill,
I believe that is the factory location, at least for the early production of the Cadets, and probably for some or all of Dart production as well. Production was moved to Wichita, KS in early October 1940, and most of the factory there is still standing too. There are several photos of the AB-xxx airplane at the Wichita plant (the one that is in the home page photos), so I thought it might be the first produced there, but Stan Piteau's notes show that it was actually the second aircraft finished in Wichita. Somewhere in my notes I have the serial numbers for those two. I'm going to send you some photos of the Wichita factory as it appeared in April 2008.
Brett