Trying to decipher the serial number for a date code. 60s or 70s Schwinn “Fair Lady”stingray.

My son has been saving this for quite some time to restore it. I believe it was originally his wife’s mother‘s at one time. The S/N looks like JF 32029. We would love to dig up the model a year. It says it was built in Chicago on the front Schwinn emblem. Thanks!