I am planning on adding more attic insulation to a house that was built in 1960 and would appreciate some advise.

The little bit of insulation that was installed back in 1960 was 3 inches between the rafters. This insulation has a paper backing but not like todays paper backing as the paper has no asphalt on the paper which lead me to believe it is really not a vapor barrier. In addition this paper backing is facing the exterior of the house.

Should I just disreguard the old paper backing on the old insualtion and proceed as if there were no vapor barrier at all and use unfaced insulation on top of the old insulation ?

If the attic is ventilated no vapor retarder is required and you could install unfaced insulation directly over the existing insulation.

Presuming the insulation is in the floor joists, not in the rafters, you could remove the paper facing or turn the insulation over so that the paper is facing down toward the rooms below.