Just an opinion, save the original parts whenever, hang'm on the wall or store in box, eBay a set of later shorter covers with the neat brace. Costs a couple bucks from a breaker, if you ever pass the bike on it can all be put back to a slab cruncher. The time and effort cutting up good parts ain't worth throwing cut parts in the dumpster down the line. Two cents FWIW.
Should mention, looks like yer bike has the early fork tubes, the shorty later fender won't work, no place to bolt it up. Oh well, I tried.