Assuming it's an Amati, your best bet is to look at pics of different Amati saxes on the web and identify which model it is. That'll give you a starting point.
Most of the Corton I've seen were manufactoried in the 70's and they were also made by Amati. They rumour says that Corton saxes were also made in former East-Gemany (DDR) but I've never seen one. The Corton Deluxe was a Yangisawa stencil also from the 70's. Serial # on stencils can be "tricky"! Some follow the manufactor and other distributors/brandholder had thier own serial #.
Thanks Thomas. I currently own a corton badged Lafleur bought brand new in 1983. I am aware of the history of Corton and their various badges, stencil and current production. I'm looking at a specific alto that was bought new and never played. Just trying to date it. Don't know if it's a bargain or a booby prize lol. But I do like them.
As always.... Depends. The resale value isn't that high, so if expensive work is needed, you've overcapitalised. If it's in good nick, doesn't need much spending on it, then yes.
Built like a tank with a very simple action. After playing the G4M for a couple or three years I find the LH table is in the wrong place for me these days. When I play it my pinky completely misses the table.