Help with Mariner/Yamaha 9.9

[HERITAGE CYCLES]

I just purchased a Mariner 9.9 HP. Model/Serial is
682CS 042456 Could anyone please help in what year is this motor. Also, looking at parts list for Yamaha 9.9 ESK, ELK,SK, and LK, what is the difference in these models. All parts appear the same. Which would be the same or closest to my 682CS 042456 Thanks very much in advance for your time

[boats.net]

Mariner doesn't list the year but it is an 1985 or older. The 84 Yamaha would probably be the closest match but not sure if is the same or not.