Very easy to connect a proper gauge on them. That way you'll know for sure. Them oil pumps can push over 100 PSI cold. The idiot light, altough I don't have the specs here should come on at around 12-15 PSI. Lots of bad things can happen to them engines between 15 PSI and the normal operating oil pressure.
That would be a better question for the Airheads in Old's Cool then they can go on about the proper mounting/measurements of them oil filters.