[jrblasde]

I believe I have finally found the correct radio which has the model 610 chassis installed in it. Courtesy of radiomuseum.org, I believe it is a model WP150. Take a look at this: 

https://www.radiomuseum.org/r/spiegel_w150.html

It’s a bit older than I thought. I had figured it was a 1942 or ‘43 model since it first appeared in the 1943 volume XIII edition of the Rider’s manual, but this indicates it is a 1939 model. The Rider’s manual listed several models which used the 610 chassis, including the model W150. I’ve been unable to find a W150, but this model WP150 looks like the one. Same tubes as well.