Guildâs iconic M-20 was the first guitar off the production line 1967, when the company had grown so much that they relocated to a new factory in Westerly, RI. Nearly 50 years later, history has repeated itself in a brand new, state-of-the-art facility in California. The M-20 is a concert size acoustic guitar built with a solid mahogany top, back and sides. It features a rosewood bridge and fingerboard, bone nut and saddle and an extremely light satin finish that allows this guitar to truly sing. The M-20âs modest appointments include a vintage style rosette and Guildâs peak logo inlaid in mother-of-pearl on the headstock. Each M-20 comes with a hand-signed, numbered certificate of authenticity and ships with a hardshell case.