I am trying to replace both of my 02 sensors on my 95 3.0... Some people tell me that the front one is an a/f sensor and not an o2..? My truck is cali emissioned with only one cat... I spent some big bucks on 2 "02 sensors".. and now im being told that I dont have two, I have one.. and the other one is a a/f sensor...

anyone help out?

They're both O2 sensors. The one in front of the cat is used by the ECU to control the fuel mixture, and IIRC, the rear basically monitors the converter performance.