[KULTULZ]

Again, those are reinforcing plates. They were used with the original flex-plate install and used with the SERVICE REPLACEMENT flex-plate install he is showing (same PN and number of reinforcing plates).

I doubt if anything needs to be re-balanced as FORD would have the same balance between the early and late or most likely would have not superseded the original part with the later design.

Proper attaching cap screw length and grade must also be verified.

How they are placed will affect ring gear - starter drive engagement position as well as convertor to front pump engagement clearance.

The FORDOMATIC SHOP MANUAL is a must here if there were no plates on disassembly.