KB107 (0.30) Pistons undersized?

Block was bored 0.030 over and supposedly ran well before I got it. It went to the machine shop for checking/cleaning/honing. Machinist didn't bore it. He told me it looked good and didn't need boring.

He did have it balanced: pistons, rings, rods (SCAT) and crank. If we have to go to 0.040 and return/replace the pistons and rings, it's gonna weigh more. I suppose it will need rebalancing again?