Only if you have an issue with the other side, if there is rust on the piston while extended it can be cleaned off. The rubber seal that goes around the piston should be changed if you can get them. The new caliper will come with one, and service info states to put some rubber grease under the seal to prevent dirt and rust from developing on the piston. I'll see if I can find out which type, they recommend. If you feel uncertain about the other side and there's rust build up, and can afford to buy a 2nd caliper, go ahead. You just don't want to rotate that piston in with any rust build up on it. That can cause it to stick in the future. If you have uneven pad wear from side to side on either the front or rear calipers, that indicates one piston is not moving as much as the other side.
Here are a couple of guides to help. And I'll see if I can find that type of rubber grease as in the diagrams.
One other thing, with the piston that won't move, have you tried pushing it in and rotating at the same time? Sometimes due to that rust, they get stuck on the outer edge. If you can clean some of the rust off, you might be able to get it to move. I know they can be difficult after so many years, especially if you live in an area where they use a lot of salt on the roads during winter.
They do sell these seal kits with a little packet of the grease, but looking at your picture again, was the seal missing on the piston when you took it apart?
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Wednesday, April 19th, 2023 AT 10:43 AM