Wrapping up my fix on this. I was able to fix my oil gauge reading. My oil gauge on the cluster pegged at max after engine start. It hits the stop at max. This is a different issue than what most people experience which is the gauge reading zero (this seems to be related to bad oil pressure sending unit). I replaced the oil pressure sending unit and the gauge was still pegged at max.
As I addressed other issues with my 95 MT5 NSX eventually this was the only issue that bothered me. So I ordered new gauges from Japan which comes as a unit that includes the temperature gauge. When I got the unit I realized I had order the wrong part since the graphics was slightly different, that would bother me to no end if I installed it. So I decided to remove the graphics from my old unit to put on the new unit. This required removing the needles from the gauges (I used the two spoons method - see Youtube) and peeling the graphics off each (held by strips of double sided tape). The graphics are self aligned so easy to install. The real trick is how to align the needles to show the right readings. This involved trial and error by installing the needle, bring car to operating temperature and RPM, see where the needles are, make a mark on the spline of the gauge motor, remove the needles and put them back on, try again. After about 7 tries, I was able to get the needles to show the correct operating marks.
Looking back, I think my original gauges were fine. At some point, one of the previous owners must have removed the needle for some reason (replace with yellow Type R needles?) and didn't put it back at the right place. If you were replacing the gauges for some reason, I would recommend checking to make sure you get the right part and not mess with the needles, particularly with the RPM and Speed needles, where good enough is not an option.