Your best guess??

Hello! This is my grandfather's Washburn mandolin that I just had restrung so that my son can learn to play it. Other than something strange going on with the varnish on the head, it is in really good condition and I'm guessing that Grandpa purchased it in the 1970s or early 1980s. My elderly mom however, thinks this is the same mandolin that he played during her childhood (mid-1930s and 1940s). There are no serial numbers that I can find. I've reached out to Washburn for help, but thought that you all might also be able to advise.

Thanks!

"Washburn" was originally a brand name for the big Chicago music firm Lyon & Healy; it was George Lyon's middle name, and L & H used it to label their higher-end line of stringed instruments. The label was later sold to the distributor Tonk Brothers, which went out of business in 1947.

Starting in the mid-1960's, a company out of Chicago called U.S. Music Co. started using the "Washburn" brand name on imported instruments from Asia. It looks pretty clear to me that this is one of those imports, which would preclude it being played in the 1930-40's. If you visit the Washburn Guitars website, you can read a lot of, well, bunk about Washburn's "storied history," but that history pertains to the L & H-made instruments, not the current line of serviceable Asian imports -- which were first made in Japan, then by Samick in Korea, and now in China.

The mandolin is an early modern era Washburn. It was built in either Japan or South Korea.
It bears no resemblance to the mandolins made by the original Washburn Company, which was out of business by the early 1940's.