Looks like a stock piston or stock replacement to me.

Go to the parts store and buy a replacement piston for your engine model year and oversize.
Buy one set of rings to match.
Install new piston.
Install rings.
Put engine back together.
Start engine and run through two or three full-throttle/closed-throttle cycles.
Take it out on the road and do the same thing.

You're now ready to drive or race or whatever.

Stock replacement pistons are built to match factory blueprint weight within the factory tolerances. If you're not replacing all the pistons save your money and don't rebalance. You'll never notice the difference.

If you are replacing all the pistons, go for some that weigh much less than the factory (720 grams without pins). Somewhere around 500 grams is a nice area. Then you will have to rebalance, but you'll notice a difference from the lighter pistons every time you accelerate.

R.