No model of instrument stands alone. Over the years, models change and are discontinued, derivatives are created, etc. Eventually it is possible to create a "family tree". Here I have drawn two such family trees, the first of the New York Symphony/Victor family, the second for the Connstellation family. See graphics below
Conn didn't (officially) identify models as being "Mark I" or "Mark II". To distinguish between variations in design from one year to the next in the graphic I have used "Mk I", "Mk II" etc. These are strictly my own additions. The "6A/6B Victor Mk II" and "10A/10B Victor Mk II" in the New York Symphony/Victor family tree are included for sake of completeness, since these instruments actually belong in the "Connstellation" family tree. The instruments are grouped in columns by features: brass bell, brass bell with nickel trim, coprion bell, coprion bell with nickel trim, etc.
The New York Symphony/Victor Family
The Connstellation Family