1. <From top view> you can see the notch in the middle of Transistor.
2. The way I go to verify the transistor: I am going to test the resistance between pin1 and pin3 and the correct value shouldn't be over 80 Ohm (fake one is always over 80 Ohm).
3. MOSFET Curve Tracer's result, which must be the same with the original vendor provided and please also check my attached file.
2sk109BL X1pcs 2sk389bl X1pcs
ebay-018
See IDSS matching data on the graph
VDS=10v
VGS=0v
IDS= Matched