Yes, upright is a service position.

Take all the balls out, lift and pull the playfield forward towards you and set the rear of the underside handles on the lockdown bar receiver (metal channel fastened to the front inside of the cabinet.

Now, from this position, lift the front with the handles and pull it towards you slightly until you feel a bit of resistance, this is the back supports hitting the stop. Now lift it straight up, arcing so that the metal arch on the top leans against the top of the head. You want the bottom of it as far forward on the cabinet support rails as it will go so the playfied leans against the head, but don't pull it too far over the stops.

When done, lower it down onto the service handles, then lift it slighly and push into the cabinet. Lift the backside to help it over the hump, then set it in place.

Main thing is being careful to not pull the playfield past the rear stops, that will dump it into the cabinet and you'll have to lift it back onto the rails.