I purchased new mounts at the dealer. I decided I'd rather change mounts in the future than to have vibrations in the passenger cabin.
On my 88 XJ I had to remove the oil filter mount to get the through bolt out. So make sure you get the set of O-rings for the oil filter mount from the dealer before you start.
When you change the engine mount only do one side at at time. If you try to do both then you may drop the engine. Make sure you jack up the engine at the bellmount attachement to the block. Do not lift with the oil pan, you can damage the pan.
I also found it easier if you put the XJ chassis on jackstands then remove the front tires so the axle drops down. This will make jacking the engine easier since the weight is off the suspenion. If you don't remove the front wheels you will first lift the whole chassis and once suspension has traveled it full distance then you start lifting.
In the early 90s Chrylser put out a TSB to change bolt torque on the trough bolt due to problems. The only place I found this revised torque was on
www.alldatadiy.com. I recommend you have a subscription for jobs like this.
Also you should replace the transmission mount. My dealer told me they change all 3 mounts at one time, if one is failed the other two are close behind.
I vote on getting your mounts from your local Jeep dealer. They were MUCH better looking than the anchor brand ones I picked up at the local parts store.