What if you are on Verizon? I cannot use those codes.
SW Version, PDA, CSC and Modem - *#1234#
SW & HW Info - *#12580369#
Test mode - *#0*#
Service Mode - *#197328640#
ADC Reading - *#0228#
Bluetooth Test Mode - *#232331#
Bluetooth Address - *#232337#
Ciphering Information - *#32489#
Or you can try *#06# this code will give you the IMEI number of the device. If it does not or it does not match, your phone is fake.
Try the codes mentioned above to check your phones authenticity.