Hi Pat,
Congratulations! What a great piece of history. I'm sure that Ted McGraw (member "Ted" here) would appreciate hearing from you. Some of the older Chicago musicians with an interest in history, such as flute player Kevin Henry, might be good to contact. Although Kevin arrived on the scene from Ireland in the 1950s if I'm not mistaken, he did meet the older musicians who had grown up in Chicago or emigrated earlier. Another Treacy accordion is known, a small 1-row Baldoni box, but I'm not sure who has it these days. You would be welcome to email or PM me any time for further information or contact emails.
Apologies if the following is off-topic to your question, but on the general features of your accordion, and similar ones:
I have played a couple similar large 2-row D/C# Walters boxes and they have a wonderful, full rich sound. They can be played for older forms of traditional dance music but perhaps were designed especially to accommodate more chromatic songs (and compete with the drums and horns) in the mid-20th century Irish-American dance orchestras.*
Take good care of that beauty. She was probably one of a kind when first made and one like her might not be made again.
Paul Groff
* Pat, as you probably know (but for others who may read this topic), the wonderful recordings of Gene Kelly on this LP (with separate recordings of Cuz Teahan) feature mostly traditional dance tunes on Gene's large two-row Walters box:
http://collectorsfrenzy.com/details/110743232799/Terry_Teahan__Gene_Kelly__Old_Time_Irish_Music_in_America__EXAnd for another aspect of the mid-20th century Irish-American orchestra repertoire, I have a feeling that Mickey Carton's huge accordion heard in the mix here may also have been a large 2-row Walters (sorry about the sad theme):
http://www.youtube.com/watch?v=l1ivIzlQtDoHere's a photo of Mickey and his giant accordion shared by Hugh O'Rourke to the Traditional Irish Button Accordion facebook page:
https://www.facebook.com/photo.php?fbid=10150342057874531&set=o.329320026040&type=3&theater