There should be four small, lightly stamped digits in the head badge. This represents the assembly date of the bike. The first three digits are the day of the year (001-366), and the last digit is the last digit of the year.

Grey Firemist was a 1986 model year color for the Sprint.

http://www.trfindley.com/flschwinn_1...986Ltwt26.html

http://www.trfindley.com/flschwinn_1...986Ltwt27.html