96 ZJ 5.2? on 02 sensors

Allrighty I replaced the entire exhaust cat and all. I bought two new 02 sensors and the exhaust shop installed them all. Now my question is if I do a bunch of short drives the CEL comes on and the code shows bot down stream 02's bad. I go on a long drive 30 miles or so and the CEL goes off. I am wondering are both the downstream 02 sensors the same? I had this done last fall and do not remember is the part numbers where the same or not. Thanks Mike