Based on the date code for the letters in this serial number, it was made in February of 1975.
October 1972
The Schwinn bike serial number H19577 was made in 1951.
http://www.re-cycle.com/History/Schwinn/SwnB_Serial.aspx#location
2003
August 1974
1984
1953 made between march 4th to march 31. However I didn't know the Varsity was made that early are you sure there isn't another letter in the serial number. If it has AL32165 it would be January 1975 more likely.
The name of the company was Murray Ohio Manufacturing Company- not "Murray of Ohio" as bicycle web sites seem prone to say. It NEVER had such a name and how it got morphed that way in the hobby and the Internet is a mystery. And Murray's serial numbering system had absolutely NOTHING to do with Schwinn's system.
November of 1981.
June, 1967
85
FEBRUARY 1974
I just searched for the serial number of my Schwinn Collegiate. From the same source it appears that mr850439 was manufactured in December 1980. Here is a reference: http://www.bunchobikes.com/serialnumber5.htm