Dating vintage martin guitars
1934 Most models switch to 14 fret clear of body and non slothead.Sometime around here Martin starts putting the Martin decal on the front of the peghead.Transition started in 1926 with O-17H according to Longworth.1929 Martin switches from rectangle to belly bridge (Longworth 2nd ed page 84) 1930 Oct, first time size & model number stamped on neckblock. The size and style designation was written on a paper label, glued inside the top of the instrument case. Some pre-1898 guitars have the date penciled on the top just inside the sound hole.For a short period of time they continue to stamp the back of the peghead as well.
Martin workers are allowed to build a guitar for their own use after they have been with the company a stipulated period.Happens sometime after serial number 439xx and before or at 44362.