The purpose of the "wiggly ring" is to keep the lower ring central, taking up the free space (regardless of how much space you perceive there to be!) and keeps the ring central and equi-distant all around.
Just because the original rings don't have them is no basis to leave them out.
You may find that the original ring is a little wider in its cross section thereby not needing them, whereas the newer ring may be that little bit smaller to enable the 'wiggly ring to sit behind it!! Manufacturers don't include them for fun or as an 'optional extra' after all their R&D.
When I did my engine , i put them in as supplied..... If l had left them out and for whatever reason I wasn't happy with the performance ....I wouldn't want to strip it ALL down again just to put them in!!