Thanks Jim. I'm a bit surprised that the part number for something like this would have been associated with the Comet, and not the Ford variant Falcon, unless the Falcon version was too short for the Comet application and they needed a modified part. I think we would agree that the majority of parts common across multiple car lines would be linked to a Ford car, not Mercury, with the most common probably being the "A" body full size Ford (C7A...)
While re-use of parts is common practice, I would stick to my comment that in this specific C7G example, being one of one, is uncommon, strange, odd.