Need help, age of GE furnace

Specific Inspection Topics Inspecting HVAC Systems
1

Need some help determining the age of this GE furnace Sr # 580194. My chart says the last 3 digits are the age. 1 being the year and 94 the week of manufacture. As you can see this does not make sense. Home was built in 1981. Did I read the #s wrong? Could it be the original?

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2

Serial looks like 34 to me…

3

if it is XX134 its 1981

GE went away and was acquired by Trane in the Mid 80s

4

Thanks, 34 makes sense.

5

Looked at it from my iPhone and zoomed in…