Help with furnace age

House was built in 1968

“Radiant-Aire” brand forced air gas furnace
MN: Q-120-80
SN: 23400

It looked old enough to be original, but just checking.

Any help would be appreciated!

Very often on those old furnaces the date is on the Fan cage

I think the term “Beyond service life” applies here!

I can’t go back and look at it again.

Thanks Roy