The body is ply, which was used in all wood-bodied Dobros and Nationals we've seen.
It's difficult to date, since the off-brand instruments rarely had serial numbers, but we'd guess c. This guitar was made sometime before WWII shut down production of the metal parts due to the war effort. These guitars were distributed through jobbers, and were ultimately sold through stores or catalogs, such as Sears and Montgomery Wards.
Additionally, it's well known that Regal built many resonator guitars without the Dobro or Regal name, or made for another retailer such as this example, which bears the Gretsch logo. In 1936, all California assembly had moved to Chicago. In the early 30s, the California-made National-Dobro resonator guitars were selling like hot cakes, so the Regal factory, in Chicago, was contracted to build the wood body, and install the metal parts shipped from California.
The National-Dobro/Regal connection story is fairly well known in vintage guitar circles, but it's worth repeating.
