Age for an OLD Rheem boiler

Looking for an age for this old Rheem boiler. House built 1965

Model # RGW-90B , Serial # K65ANIX 37

Looks like it could be original. Thanks in advance !

I would say 1965 going by the serial # K 65 ANIX 37

Thanks William, that’s what I was thinking also.

Agree, I would guess the K may represent the 10th month. 10/1965.