Airco Furnace Age

I have finally been stumped. Cannot figure out the age of this Airco furnace. Already checked with building center and googled it. Home is 53 years old but furnace is newer. According to what I found they went into business in 1970.
Anyone have any ideas??
Serial is 9D-123


Airco started building gas furnaces in 1956. The information I have puts the age at 1962.

Good info. Where did you find it??

Inspectors Journal