My orchestra director brought out this mando that was given to her by her mother. How do I tell what year it is? There are some weird things about it, however. On the head stock, there is no designation that it is a Gibson. Also the bridge is non adjustable. It looks similar to #50436 on the mandolin archive and has a green lined hard shell case. Any infomation on this mandolin would be greatly apreciated. I'll post some pictures later tonight.