Thank you for contacting Mearto. This is a vintage GIbson A Style mandolin.
I’ve included some additional information below about the history of Gibson mandolins.
Based on previous auction sales, the Fair Market Value of this instrument is between $1000 and $1200.

**There are very many styles and varieties of mandolins made by very many manufacturers and independent luthiers. But, typically referred to in the USA are those manufactured by the Gibson Co. (or patterned after the Gibsons).
Prior to about 1900, the typical mandolin was the Neapolitan style. The oldest surviving instrument was made by the Vinaccia family of Naples, Italy around the mid-1700's. This type of mandolin has a bowl-shaped back and a top made from a flat piece of wood bent over a hot poker forming a slight kink or ridge about where the bridge fits. This kink is important, and is what marks the advancement of luthiery credited to the Neapolitans, for it strengthens the top enough to withstand higher tension strings.
Then around 1900, Orville Gibson of Kalamazoo, Michigan created two new styles of mandolins. Inspired by the way violins are constructed, he made his mandolins with a carved back (much flatter than the bowl-back of the Neapolitans, but carved to shape, none the less) and, importantly, the top carved in an arched shape. The plainer of the two styles he called his "A" style - it has a simple round teardrop shape profile to the body and a simple plain peghead. His other fancier style he called his "F" - it has a fancy body profile with projecting points and scroll and the peghead is likewise of a fancy shape. [It is said that these designations were short for "Artist" and "Florentine", but the names are confusing because they have been applied by the Gibson Co. and other makers to various other styles of mandolins. The letter designations, A and F, have been more consistently applied to the styles described.]
Source: http://www.vintagemandolin.com/mandohistory.html