Every area is different. In our area we use air to blow out the well and a bailer to dip out the sand and surge the gravel pack into place. Then yes we use the customers pump to pump out the well because there is very little sand left to pump out. Test pumping a well or developing the well with a pump, I would clean the well out with an old pump of my own before putting in the customers new pump.
Many decades ago I sold Reda pumps that had a one year unconditional warranty. A lot of pump installers would use them to clean up a well, then bring them back to me for warranty replacement. Reda pumps cost more and lasted a long, long time in clean water. So many pump installers would install a cheaper, shorter lived pumps after cleaning the well with the Reda. Wonder why they don’t make those kind of Reda pumps any more? lol