I'm a big fan of canning so I'd say you should try it at least if you haven't already.
Anyway, there are usually two parts, the lid and the ring. For some reason, the rings get corroded, rusty or just don't look nice after awhile. Happens to mine all the time. But if the lid is fine, then there's no reason to replace it. When you can, the ring is simply to lock the lid in place during the water bath. After the can has sealed, you can remove the ring. Some people remove it, some don't. You can't reseal with a used lid but I re use the rings all the time and not all in perfect condition. Your lid doesn't look that bad.
I've been keeping my preserved lemons in an old ceramic crock. I added a little vinegar to top them off and they seem to be doing fine. ( I just checked them.)