No O2 Sensor?

Hi, I am about to replace my downpipe (92 XJ) with another stock one that came off another XJ that is around the same age (dont know for sure the year). Well my current set up has the O2 sensor attached to the down pipe right where it bends to get to the headers. The pip I am going to replace it with doesn't even have a hole or any spot for a sensor....do I have the wrong year? What should I do?
Sorry if this is an idiot question.
-Rob

My 87 has no holes in the down pipe, the o2 is in the header right where all the pipes come together, just before the down pipe.