The "Eminger" report, in actuality, is a Ford to Dealer invoice, an original Ford document. It is one of the most accurate reports to have on your vehicle. If a feature or option is not listed on the Ford Invoice (Eminger report), it didn't leave the factory with it.
So, as nice as the Marti report is, it is a compilation of what Marti's staff interprets from the invoices on the vehicle. So sometimes, the terminology and what they list in the feature section differ from what is on the Ford invoice. And.... I'm not slamming Marti; I have a small fortune in Marti reports on my vehicles.
I mistakenly thought your car was originally a Q code and was replaced with a '70 M code engine. So if your Mach1 were originally an H code, then the FMX would be correct. So yeah, using the VIN on the engine and trans are out!
The A/C Non-A/C firewall pictures posted by Hemikiller were great info from him, as usual. You would definitely have to be a self-punisher to attempt to duplicate factory air. There is a good reason Ford calls it "Integral" AC! The Ford dealer installed air-used lower dashboard-mounted controls and outlets. It did not utilize the same dashboard vents as the heat and factory air use. It could also be a mix of aftermarket and Ford components.
Front clipping was a common practice in those days. Those were big sellers for the salvage yards. As I said, not something I was convinced was safe, at least not for me, as hard as I beat on my cars.
The build sheets were just an afterthought by the line workers. They could just as well absent-mindedly throw them in a trash can. They had codes on them that meant something to the line workers but little else to the dealer or buying customer. Little did they know how coveted these would be 50+ years later! They have been found under the carpet on the front and rear floorboards, under the rear seat area, and stuck into the seat frames on the front and rear seats. And as you mentioned, some were not in any cars. (Trash can ate those)!
There is one more option to possibly verify the VIN I hadn't mentioned earlier. There is a thin metal tag fastened to the front of the radiator support called a buck tag. The assembly plant body shop used it to assemble the body to ensure the proper pieces of sheet metal and metal fasteners were used. Different trim levels on the body styles, A/C-Non A/C, types of mirrors, single or dual exhaust, suspension packages, etc., all required different fasteners, holes, and metal panels in the body process. Most importantly, it has the complete vehicle Vin embossed on it. In '71, it was on the passenger side; for '72s, I've found them on both the passenger and driver sides. In '73, they were all on the driver's side.
Unfortunately, they were fragile and easily damaged. Many were thrown away along with damaged sheet metal if the vehicle was ever in a front-end collision. Many were damaged when caught on a mechanic's tools, air hose, or arm. Hopefully, this 50+-year-old piece is still on your car.
The illustration below shows a buck tag on a '73 Mach1 with the complete vin marked with the red rectangle. This is located on the radiator support behind the headlamp bucket. On your '72, it could be on either side.
Once again, fingers crossed!
View attachment 77066