Congratulations, Dave. Nice find. It even has its 5AP4, which might still be good.
We have accounted for 23 factory made sets, plus 11 of the kit models, which use a very similar chassis:
http://www.earlytelevision.org/database_prewar.html
About 15 prewar sets become known to us every year:
http://www.earlytelevision.org/sets_added.html
Some of these have been in the hands of collectors for years and have just been reported to us, but most are new finds, such as Dave's.