First, welcome aboard.
There are guys here like George and Boss Wrench that know more about these cars than we will ever know. It's mind blowing the knowledge they have.
I also have a GTS that has the same carb / manifold set up but mine is a Euro model. I was also questioning the originality of the carb manifold but decided to let it be. Being a post Ford car it's hard to know for sure so why care ? The Ford Pantera's have better traceability so you are lucky.
These are easy cars to understand and to work on provided you have basic mechanical skills and manuals. Other than a transaxle I would say have at it and don't be afraid to ask because this is the place for answers. No such thing as a dumb question.
And yes, many of us have told the other half we would sell after a restore but few admit it . All for fun.