You can look on remington's website, but judging by the serial number it should have been made in 1980.
Impossible to answer without the sn.
see related links for chart and barrel code info.
See related links for information on barrel code dates.
You can tell the age from the date stamp on the barrel. Check the manufactured date page on the Remington Society of America to look up the details.
They are date code stamped on the barrel on left side in front of receiver. A barrel location diagram and the date code table (month/year) is available on the Remington Society of America.
Can't be answered without a serial number.
Impossible to answer without the serial number.
You cannot tell by the s/n. You need the barrel code, located on barrel, left side, at the frame. Find that number, post it and I'll see if I can help.
1914
1920
Manufactured 1927
Made 1912