Glowshift in cab Fuel Pressure Gauge?

[Waterloo]

I was thinking the old girl is getting up there in years, much of the fuel system is from the first in frame, just seeing a few IFSM equipped trucks now having fueling issues, so thinking maybe a fuel pressure gauge may not be a bad idea to possibly catch a failing pump on the old 2008 ProStar CM-871.

I was under the hood yesterday, still at the house... Getting ready to leave, one of these days...

I was just glancing at all of this yesterday, not much thought going on as I was messing around elsewhere, but had the phone and took a few photos...

Anyway, I took a photo of the side of the IFSM, there is a compucheck port, and wondering if this is a spot that a fuel pressure sending unit can be installed? Or would it be the bottom port, with the nipple on it at the nose of the unit, below the where the main fuel line exits the IFSM. Or, where Pd6 has his down by the fuel filter? I don't know if I will do this, just thinking outside of the box, and the gauge is available...