Very Nice... AK's are very desirable and that look like a mint example. Someone put a lot of work into it. Those chassis don't survive 70+ years that clean, its been restored. The RCA tube is not correct. The restorer used an equivilent in place of the original type 80 rectifier with a diferent base.
Very Very nice, Atwater Kents first superheterodyne.
Here are the schematics
http://www.nostalgiaair.org/Resources/458/M0001458.htm
Steve