It might be because of the plastic cam cover. You need different bolts to fit the ally cover the older SE have, also the Vec C doesn't use the cam to drive the power steering so that is slightly different also.???
This is the Z22YH
This is the Z22SE
Notice the fuel rail on the SE and also the visible coil pack, also the Yh has that strange round thing coming from cam breather, some sort of collector.