What's the difference? O2 sensors.

Well, I went through all 8 pages to see if there was another thread about O2sensors and the only one I came across was from a guy who wanted to install one him self.
I visited www.oxygengeeks.com (http://www.oxygengeeks.com) and they had a good informative on the difference between O2 sensors and an AFRS ( Air Fuel Ratio Sensor). They work the same way but are cunstructed differently. According to this site only Toyota and Honda have these types of sensors but not entirely. If the numbers on the sensors start with 89467 it's an AFRS, if it starts with 89465 it's a O2 sensor.
My problem: My sensors are original from factory. They don't have any numbers inscribed into them. They have little tags on the wires but what ever info was on there is completely faded. I have to replace them due to age. I checked them with my scanner and it doesn't read a signal from the sensors. I thought maybe it was a glitch and tested the scanner on my wifes' 04 Sienna and it works well. So now I am wondering if any one knows if a 97 Rav4 with the 3S-FE engine has an O2 sensor or an AFRS. I'm going to call the dealer tomarrow but I'm not looking forward to dealing with them too much. The dealer close to me doesn't instill much confidence in me. They haven't been very helpful or knowledgeable for the few problems that I've had in the past with this Rav.
I'de much rather wait to see if any one has the answer before I call the dealer.

A bit late but, for anyone else wondering, if the car has california emissions it uses AF ratio sensors, otherwise, it uses standard O2 sensors.