Of course that is BS, we can all point out similar units at dealerships with a later build date that than those sitting incomplete. It is far more economical to install parts on the line as intended than give it to some outside contractor, drive to some obscure lot, find that vehicle, install the part, and drive back. Not sure who they are trying to kid.
It does seem logical though, instead of using outside contractors, use their own employees who might be laid off for the week. Using 3rd party contractors could mean it will be Christmas of 2025 before they get the mess cleaned up!