I am not near the car so I cannot take a photo to post, but the service manuals for both 2011 and 2015 show the motor serial number on the side of the motor toward the front of the car (on the actual electric motor, not other components mounted above it). You should be able to see it without disassembling anything by looking down behind the radiator while standing in front of the car (motor is down low and somewhat cylindrical in shape).
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015; traded 8/10/2019 at 82,436 miles
White LEAF 2019 SL+ purchased 8/10/2019