i'm not sure but i'm not worried about it. piston still moves about in the cylinder, theres no scrathes on the walls and the rings are free. I have for other pistons but i would think using a different piston would be riskier than just leaving it be
As long as the piston is not cracked, and there is no visible wall damage, run it....for many more miles.
It may have a bent rod but may not do much if anything even if bent, highly likely bottom end good to go.
I still have that block, and the 96 ej25 that came out of the car, plus the heads i put all new valves in from a 97-98. And i just bought a jdm ej25 locally and tore it all apart and put my head gasket kit in it and the rest of the seals. the motor had virtually no wear inside and although i didnt change any of the timing stuff, the belt and pullies all felt like new. the old owner said it only had like 50k miles on it but who knows how true that is. He pulled it from his outback and he must have hit it with something because the right side valve cover has damage, minimal but i need to go get a valve cover to finish the swap. i'm bummed out cause we just got two snow storms and i swapped in a lsd earlier while i was waiting for parts to come in. Now im just on the fence to change out the 236kmil 5mt while the motors out or wait til i need one or a clutch