Old Lennox age please !

Can’t make heads or tails out of these numbers. These were the only numbers on this unit. Model # GH6-120M , next to it was a metal plate with ID# GH6-120M-2 , in the blower compartment was a similar metal plate stamped with ID# H210 3/4 - 7 - M - 2 - B.

The house was built in 1925, I suspect the furnace may be from the 50’ or 60’s . This was the only info on the unit. Thanks in advance for any help…Rick

1965 120,000 btu’s

Thanks Michael !