This Martin Guitar Co. catalogue is dated January 1928. I have not seen this catalog previously, even in the Martin archive.

This information is only available due to the indulgence of the National Music Museum in allowing me to conduct research in their remarkable archive. Anyone wishing to obtain information for their own research interests should contact Arian Sheets (Arian.Sheets@usd.edu). For those who want to show a little love to the National Music Museum for making this information available please consider making a small donation to the museum or becoming a member of the museum (https://www.nmmusd.org/support-us). The museum also has a collection of remarkable guitars (actually, every kind of instrument!), a visit if you are in the area would be well worth the effort.