The center hole is not plastic...!!! It's some kind of metal...
Don't compare the 07 bar you have with a 2010 bar!
Please refine which swivel loops have been working 100% through time?
The pulleys don't fail as a swivel since the pulleys work differently than the swivel!
I through loops as well but now i am starting to loop from the other way so that's even better

The 5th line bar is the same just the fifth line is attached within the 2 front lines!
I will post some pictures tomorrow of the bar
All the best...