Aging out old Weather King condensers by Addison Products Co

Trying to get the ages of 2 condensers by Weather King. Building intelligence doesn’t have this 11 number serial number format. I saw some other posts on this but cant figure out how they are figuring out the ages. Im thinking 1986 and 1987 but im not sure. Home was built in 1988 and these were in pretty rough shape. Thanks for any help with this

Unit #1
Model # SFC918C-1
Serial # 28607168189
Unit #2
Model # SFC930C-1
Serial # 28704152233

Post a pic of the data plate.


Definitely '86, they sold/merged the company in '89.

Awesome, thanks Dominic