Its a depletion mode FET so an Ohm meter will only find the source and drain pins. It is possible (although unlikely) to damage the FET by applying the meter probe voltage on the gate pin.
I suggest going to that well known auction site and searching for "LCR ESR" and buying the cheapest open PCB unit it offers. They are surprisingly accurate for the price and by placing the FET pins in the ZIF socket it will identify and show the pin out on the LCD.
Brian.