I have a balancing question that I cannot find the answer to.

I just had a 383 stroker built. I used a Liberty 4340 forged crank that is internally balanced on the front and externally balanced on the rear. I used a Dart SHP block with a 1 peice rear main seal.

the rotating assembly was balanced without the flywheel on. ( I do not know why) the shop took my externally balanced flywheel and nuetrally balanced it. Is this correct? The crank externally balanced on the rear and I thought 1 peice rear main seal also called for a externally balanced flywheel. am i missing something?

thanks