Until 1936 Pierce Airo used the trade name DeWald.
From 1937 on DeWald was the manufacturers name.
To avoid misallocations and double uploads and to allow easier search both manufacturers (if there is any difference ?) are put together in DeWald as a pool.
The accurate allocation is found at the individual models.

The problem is, that most literature does not clearly distinguish, and even Pierce Airo radios may bear the name DeWald. And that will be searched for, not for a hidden name