I don't know for sure, but I would think the computer will adjust the F/A mix for this at warm cruise without seting a code. Providing the O2 sensor is fuctioning properly.
Now, during self test the computer may test for this and set a code.
But, like you say, easy enough to test out.
Vinny...
"Do All Scheduled Maintenance Prior To Troubleshooting"
"Resolve All Known Issues Prior To Troubleshooting"