GMC Repair: 5.7L V8 gas engine - oil pressure, oil pressure switch, engine oil pressure

Question
novice Q:

I'm looking to buy a used 11 ft step-van with an intermittent "oil pressure
light" warning. The vehicle is a long distance away and I'm trying to determine
what I can do to verify that the engine does not need replacement.

I do shade tree mechanics and have never done an oil pressure test on an
engine. The following are simplistic questions coming from almost complete
ignorance so your help at pointing me in the right direction is appreciated.

1) Are all oil pressure gages the same or are they engine specific? Just so
long as the gage scale is in the required range it is good to go?

2) Where and how do I tie into the oil system with the gage?

3) If the tie in is a male thread insert connection will a gage typically come
with a selection of threaded attachments?

4) Since I see needing to drive the vehicle to check the oil pressure during
operation will I be looking to buy an extension hose to feed the gage to the
drivers seat?

Thank you.

Answer
most oil gauges all read the same, as for it tying into the engine, a good kit will have many adapters to fit many vehicles, you would be unscrewing the oil pressure switch from the engine block and then threading in the appropriate adapter and monitoring the pressure from there