If you are going from a Lightning to a Uly, You need to swap out the side mounts and a top cover/mount that the windscreen mounts to and obviously the fly screen too. If you are going the other way and have a Uly and want a Lightning front you will need just the side mounts and the fly screen.
Here are some pics of what need to be replaced or gotten from the Uly to Lightning. Overall it is a simple swap.