I don't remember having to grind any of the rivets off and would think hard about doing anything that is not reversible. You do have to take the lock apart to get the spring in and it is a little tricky to put back together. If you look at the flat part of the latch on the inside of the lock there is a small box and in the box is a lubricating wipe. When you take the lock apart the wipe can fall out. Slip a thin strip of hard plastic between the latch and the box to keep it in place as you take apart the box. It seemed to be treated in a graphite material so it can be messy. There are also brass spring washers that hold tension on the various latch and mechanisms. They can be damaged when you taking the latch apart. If you can take the other latch off it will serve as a reference to help you to put the damaged on back together.
Brian