Just had a check engine light come on and stopped at Autozone. Bank 1 02 sensor was the problem (P0133). slow to respond

So that's passenger side 02 sensor.

Should I just replace it (truck is at 129xxx and I have a feeling it hasn't been done) or should I try some other methods to clean the system ( and what would those be?)

I gave a quick look and don't see anything bad with the wires but there does seem to be a dent in the sensor itself.

 

I would change it out. A slow to respond is code that deals with the performance of the sensor itself.

 

Yeah the sensor is on it's way out. Just make sure there isn't anything contaminating the sensor or connection (like oil or coolant) or you will kill the new sensor as well.