When to Use O-Ring on P/S Pressure Hose?

This power steering pump was attached to the '65 Formula S when I purchased it and I have no idea if it is original to the vehicle or if it is a replacement from another year/model.

Anyone expert enough to classify this hose fitting and tell us if it seals with/without an o-ring? Thank you.

power steering pump hanging 1.jpg

my red power steering pump.JPG

p:s hose oring question.JPG