Dodge - Durango :: Oil Pressure Dropping To 0 For A While / Engine Revving Really High

My oil pressure had been dropping to 0 for a while. After searching the internet, I replaced the oil sending unit. This seemed to fix the issue for a while - until I was going up some hills, and the engine began revving really high, and the oil pressure once again dropped to 0. I then heard some noise from the engine, so I pulled over and turned it off. I had it towed to a garage, and told the tow driver to NOT start the car, because I thought the oil pump was out, and so no oil was getting to the engine.

I then called the garage, and told them it was coming in, and NOT to start it, because the engine was not getting oil, and I thought oil pump might be bad. They called me back an hour later to tell me they had added some oil and started it, and the engine was gone.

First question, is would a good garage have tried starting the car with the information they had? My expectation was that they would have tried to check things out without starting it.

Second, should I try to replace the oil pump and see if the car starts?

Make: dodge
Model: durango
Model Year: 2000
Odometer Mileage: 205,000
Amount of oil consumed between oil changes: 1 qt
Frequency of oil changes, in terms of both odometer mileage and elapsed time: 6months, 5000 miles
Oil level was checked once every one to two weeks.