I would get the block and head resurfaced, throw on a new HG and new ARP studs you should be good to go. I cant tell if that one piston is good or not but they look clean and the cylinders look good. I dont know if you can get the block decked without removing the pistons?? Maybe for and extra precaution have the engine disassembled and have everything checked. Thats what I would have done.