273 piston weight comparison
I'm not sure they worry about the individual pistons.
My understanding they want all the piston and rod assemblies to match each other (all assemblies the same).
The crank then needs to be matched to the assemblies.
The damper/balancer needs to be neutrally balanced (by it self).
So yes, you will need to start over.
A good shop will weigh all the pistons and all the rods and then try to pair them up to minimize the amount of grinding.
Alan