This information is from this site: http://cderksen.home.xs4all.nl/PanAmNModels.html
CDerksen indicates that there is a connection with Pan Am and Conn. Did Con buy out Pan Am?
CDerksen can be contacted via his page above, and I also would appreciate being updated by people who know about Pan Am clarinets.
This page contains a clarinet model number list. It includes models up to 1955.
I have included an extra column to indicate the year(s) when the instrument was (at least) in use. If both the "Year Introduced" and "Year Discontinued" column is filled in, the "Years Used" column is left blank (no need stating the obvious). Italics indicates "educated guess".
The following list is by no means complete or even correct. If you find an error, or know of a model of clarinet that falls into the criteria mentioned above that doesn't appear on this list or is produced outside the years indicated on this list, please let me know (see main page for e-mail).