Now did you buy the entire boot with the leather already built on, or did you just buy the $30 leather wrap?
If its just the leather, then you want to clip it to the plastic (at least my '87's was plastic) diaphram. But make sure you let the leather sit in the sun for a few hours or heat it with a hair dryer. I didn't bother to do this and the leather took some muscle to fit properly. Also, be sure to get the kinks out on the upper portion before you re-fit the cap. As me how I know