Porous surface

Another view... Some have a noticeable dent like a small one

It still needs cleaning but just wanna make sure what to do







I'm on the middle of rebuild. I found this.... 3 piston looks like has an unusual dent. It's a little tiny one that you can only see with a light in an angle. But touching them feels smooth and the dirt makes it look like cracked but is not. Im tight on budget and idk what I should do. Other pistons are in great state.