Differences Between '67-'68-'69 Barracuda Notchback/Convertible Trunk Lids

Torsion bars are what lift the decklid.
They are mounted under rear sail panel and run side to side. If you go with a fiberglass lid they wouldnt be needed.
Not sure what the torsion bars are. Is that the support structure under the skin? Does it matter if they are different? Will they fit? Given this is a RestMod project, I'm not concerned about the exact year accuracy, but certainly want things to fit properly. So if it is simply a matter that someone who's an expert on the YoY nuances might see the trunk open and noticed a '67 or '69 support structure on my '68 it wouldn't bother me. Bt if it's a fit/operational issue, I do care and hope you can clarify a bit ... many thx!