Age of Coleman gas furnace and Fedders A/C

The home I inspected yesterday had a Coleman gas furnace. The model # was G8C07512MUB11A and Ser # WCKMOO5903.

It also had Fedders condensing unit Model # C36ACD1V and Ser # EU245634139X

This does not correspond with the age charts I have. Anyone know when these were manufactured?

Furnace manufactured between 1999 and 2005.

AC - May of 2006

Thanks for the info