Ya, I didn't think mine would bolt up either, but when I took the other mounts off, the top holes weren't used and hidden in behind. It still didn't look like they would work until I actually held the new mounts right up to it.
The rubber part of the mounts, I had just left in the truck, but found out you have to modify the driver side. There is a U shaped iron that goes around the outside of the rubber (pass. side doesnt have this) So either cut the rear of the U off (I did) or swap mounts side-for-side. The iron wont interfere with anything on the pass. side (I should have swapped them, but engine was in and hindsight is 20-20). This iron hits the solenoid on the starter if left in place.