Hey Ben,
I’m pretty sure that the balance should be the same..just one will have the inca-block shock absorbing system.
You will want to replace ( swap ) the entire balance, as the hairspring and balance wheel are regulated ( vibrated ) together.
One think you may encounter is that the donor balance may be a bit different than the one you now have, which could cause some side shake or end shake issues. With older watches it can be a crap shoot
Best regards,
Randy