BTW, didn't mean to sound like I think that folks here don't know what they're talking about, just wanted to pass along a great resource that some might not have seen before. I found this post there, should help narrow it down.
Approximate dates:
1927: change from wooden pegs to patent tuners
1932: script logo added to the front
1932-34: silkscreen script logo
1934: end of bar frets (on guitars, anyway)
1935: end of back stamp (on guitars)
1962: "Made in U.S.A." stamped inside the instrument
Something else could help you: I found a Martin ukulele chart on the web site of Ukulele Club of Santa Cruz. It is a handy document (except for the outdated "Value today").
They present it as four pdf pages that you can download separately.
I put the four pages together for a single download if you prefer it that way. Note that the combined pdf is 2MB.
Click here to download the document.
You could also have a look at this: The History of Martin Ukuleles...Part II
or this: IDENTIFYING MARTIN GUITARS, MANDOLINS, AND UKULELES
Richard
Martin: 1937 0-17T*|1924 2-17*| 1935 C-1*| 1941 0-15*| 1957 00-18*| 2003 5-15 Terz*| 1-T*tenor*uke*| 1950's*Style*2*uke*| 1932-34*Style*1*uke*| 1927-31*Style*0*uke*| 1950's*Style*0*uke*| 2005*SO*uke*| 2006 Backpacker
Other