Olds Ambassador - Serial Numbers. It has the serial number '965963' stamped on the valve section and the words 'Olds Ambassador, Fullerton, Calif.' Stamped on the bell. I think it has been relacquered. The slides have lacquer on them and I'm referring to the part that is supposed to be inside the tubing. Serial number is 897801 made in 1974. This is one of the better playing ambassador trumpets that I have. What's more, Olds Ambassador trumpets can be bought from top-rated sellers on eBay, so you can confidently make your selection.