1894
1952
The Selmer saxophone with the serial number 19455 was manufactured in approximately 1947. Selmer's serial number system allows for a rough estimation of production dates, and this particular number falls within the range associated with that year.
Most likely 1970.
Around 1963.
The Selmer Series III tenor saxophone with serial number N-641270 was manufactured in 2000. Selmer typically uses a serial number system that allows for the dating of their instruments, and the "N" prefix indicates it falls within that production period.
Best estimates put this trumpet as being manufactured after 1984.
Between 1957 and 1958.
Serial numbers 68901-74500 are made in 1957
Best estimates put this trumpet as being manufactured after 1983.
1915
Selmer's website has a comprehensive list of years versus serial numbers. You can check it out yourself at the link below this box. But your's falls between 1947 and 48