Hot or cold doesn't matter that much. The important thing is to make sure the car is on level ground and if the car has been running let it stand for 5-10 minutes to allow the oil to drain back to the sump. The handbook says do it first thing in the morning before running. That way you are sure to get an accurate reading. In my experience it is also easier as the oil has not been splashing around and up the dipstick tube to confuse readings. Do 3 or 4 dips wiping clean each time to confirm reading. Do not overfill as this can lead to excess oil pressure! This is only for 3200's not dry sump engines.
Maserati do recommend to check the 3200 oil level with the engine COLD. I parked the car in the garage and checked when left for 20 mins from hot, then checked again the next morning and there was a marked difference in the level so be careful