Is there a reason my 2002 RAV4 would show false 02 sensor codes?

Only one suggestion - have *qualified personnel* perform the necessary testing to determine what has failed to cause those trouble codes .. Usually the actual problem is within the other operating systems and the O2 sensors are seeing this and reporting it to the onboard computer.

Electrician? No. Appropriately trained, skilled, experienced technician familiar with Toyota products? Yes. Pushrod is right on -- you did not mention diagnostic trouble codes, so the guess is that the "O2 sensors" is a guess based off of a code, instead of someone experienced and skilled performing an appropriate diagnostic test related to the codes retrieved.