Dating kay guitars

Mine has "S 36" stamped in red ink on the back which definitively places it as a 1936 model. This guitar appears to be a Harmony H-1390 Marquise model which the Demont Harmony database says were made from 1937 to 1940. This guitar is valuable to me for two reasons, one the history it holds and two for the age and condition that the intact pieces are in.

I picked up this instrument for a small price due to its condition but it looks to be an instrument that is worth restoring.