All wildcats are regulated. The mk1 and mk2 didn’t have reg gauges. You can install one when the stock is off to see where the reg is set, but it won’t fit with the stock on.
You need to shoot it over a chronograph. When the velocity drops off about 30 feet per second you are coming off the regulator. Check the fill pressure at that point and that should be close to where your regulator is set and time to refill.