Monteverdi 375L vs Sierra

This advert showed up on my radar:

https://classiccars.com/listings/view/1087040/1970-monteverdi-375-4-for-sale-in-saint-louis-missouri-63146

A very cool car and it came with a very nice photo slideshow. And you can see clearly the 375 gearlever and bezel which is an exact match as used on the Sierra showcar / prototipo.

Next to that we noticed the dials (speedo/rpm) are exactly the same as well.

Note the printed details in German/Deutsch (oeldruck/blinklicht/benzin) and the printed name "Monteverdi" including printed "8CYL. Very cool, I suspect they still had some on stock. These have been used at least in our Sierra.

Later/newer models had different dials. And between the speedo and rpm dial there are additional light indicators placed. For example this brochure model does have a different RPM dial (ie different needle and marking indicators) But it does have also the extra time clock added (so 4 dials in a row). Note ours does not have the extra time clock. And our dials all have Monteverdi printed on them. This isn't the case on the brochure Sierra.

The following Sierra model also has a different RPM dial and indicator lights between RPM and Speedo. However it has only 3 additonal dials (amps/water/benzin) And by the looks of it, these 3 have a different dial layout used (at least different as ours). So much for consistency.

The bench used in the back of this 375L does look familar as well. At least the backside looks similar. The upholstery pattern is identical and so is the armrest. The Sierra has a little more space below the armrest. Meaning the Sierra is slightly different though and is a little higher in length. The front chairs are different and it's mentioned on Wikipedia they are reused from a BMW, we still don't know which type/model.

Remarkably also the 375L has got this specific square hole in the boot (the 375 does not). I'm not sure about it's function. Clearly it's not fit or used for a spare tyre. So I can only conclude this is done to provide extra Luggage storage. So for the Sierra they created this extra bespoke square hole as well (I'm unaware if other Sierra's have it as well - could be only ours has it?). Perhaps the Sierra is using the same fuel tank as used on the 375L? We havent found any markings on our fuel tank - so we can't say - perhaps just a Chrysler tank which has been modified to fit?

While we are at it, it's remarkable how close the rear looks as well. I was almost inclined to say they have been using the same panels and boot lid. But the bood lid of the 375L has a slight curve towards the rear window and I'm not sure about the exact dimensions either. The profile angles used  seems slightly more sharp. But still ...

And the front is much of the same. I wondered if they share the same hood/bonnet lid? The 375L has air vents on them though and likely the Sierra is slightly shorter in lenght and by the looks of it wider too. So no.