yeah, sorry I wasnt clear on that, but as Sabre stated, the wear tabs are part of and built onto the brake pads themselves and the anti-rattle clips should be replaced when the pads are.
Now, since you stated that one side was worn more than the other, that is a big clue to a brake issue. If the right side is worn more than the other that points to an issue with that caliper.
That said, without seeing the pad and how they wore, its tough to point to something like the guide pins, caliper piston and so on. HOW the pads wore tells you which part is failing. If they work evenly, but just more than the other side, that would point possibly to a caliper piston issue. If they wore more at the top than the bottom that could point to a guide pin issue.
Knowing how the pads wore will tell you all you need. But the fact the right side is wearing more than the other, I would look at just rebuilding the whole thing and be done with it. New guide pins, new caliper piston seal, new rattle clips and so on. Rebuild kits for calipers are not expensive at all. And, dont forget about the brake fluid either. Brake fluid, because of its chemical make up, attracts moisture and over time will cause issues.
Generally speaking its wise to flush the whole brake system about every other year or so.