Did i buy the right o2 sensor?

I threw a code p0036 (bank 1 sensor 2) after installing my catback. They torched the bolts after headers to loosen them which i believe damaged one of the sensors.



I bought a Bosch pefect fit sensor. $170 at autozone w tax. No splicing needed.



Since it was bank 1 i bought cylinders 1- 3

And since it was sensor 2 i bought downstream sensor.



Autozone guy was telling me i needed upstream cause it was bank 1.



Did i buy the right one? Price seemed same as ecstuning after tax and shipping.



Thanks.



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