question on 96 sentra parts

[mrrlwang]

My car is 96 nissan sentra non-CA auto.
I orderd a header pipe and a catalytic converter
from import auto parts. the part numbers are
H3000-49566 (099-549 for bosal) and
H2000-59790 (813-761 for bosal)
But realized that both of them are wrong.
I checked the other website that provide the
OEM parts and all of them give the same parts and
parts number with the same image.
But I am sure that the converter doesn't fit my
car. There is an O2 sensor plug at the outlet of
my car, but the one with partnumber
H3000-49566 (099-549 for bosal)
does not have. I just dont know if it really fit
my car since so many sellers have the same
parts for the same car model.
Did anybody face the same problem?