I have updated this forum topic at trumpetmaster with the following:

based on what I have on model numbers, bore may be the distinguishing feature. If you can measure your horn for length, bell diameter and bore that would be appreciated. I monitor Ebay and other auction sites and search the Internet. I can use pictures, model numbers, serial numbers and anything that confirms the date of manufacture like an invoice. Please share any information you may have.

It's in the forum under vintage trumpets / cornets and titeled 'Cavalier Serial Numbers' So I have decided to do a study on to see where it could go. Additionally Cavalier seems to have a later start date. However, I could not make sense using the Pan Ameican accepted listing owing to the leading zero (0) on many of the horns I have seen or have. There is alot of speculation, including the accepted Pan American list dating as being aprapo. I think I have a tiger by the tail or maybe tale, but I am trying to understand and maybe establish the basis for the Cavalier line by Conn - that is develop a Cavalier serial number dating system much like that developed by Christine at the Conn Loyalist.

Conn trumpet serial number gk620019