Can you delineate delays if an item like "special fire wall" are coming 2 months after the project is complete?

Can you delineate delays if an item like "special fire wall" are coming 2 months after the project is complete?

I assume you can call the item above for "fairness" - if not there is no way around it being the "critical path" / "longest path" - at least per the computer - persnonally I would not call that the critical path because there is no path.  Does anyone assess liquidated damages for some one item thing?  Does it depend solely on if you call it punchlist or not if there is a temp workaround?