Furnace age?

Anybody tell me what the age of this furnace is? I think its early 70’s but want to make sure.

Model VGA 75N
Serial 2601

The Prestons book I have has VGA-75 from 1967 to 1971.

There is know N models listed

There is a VGA 55N that states 1972.

How old was the house?

Hi Dave

Thanks for the info. It was a Condo and they were built in 1971