Ok, I went out and took some pictures with my cell phone. This is my car.
A few things I can note solely from your photos:
You said your car is a 1960 750, yet I see you have 600D taillights. Does your car also have vent-windows (1/4-glass) in the doors? If so you likely have a 600D-based car, which would indicate this is (was) probably not a 750 (750 Berlinas were normally 600-based, 850TC's were 600D-based). If you don't have vent-windows, then the original 600-style taillights were likely replaced earlier.
The 850TC radiator assembly & gauge unit are obviously not original for a 750, so I'm ignoring those. Ditto on the PBS engine/head assembly & the Campagnolo wheels.
The front fender & dash emblems look to be original for the later-model 750 Berlina, but the rear decklid emblem is the earlier style. The Abarth shield on the front grille is the wrong style of scorpion for a 750 Berlina (yours is late '60's/'70's type).
I can't see the rear decklid props clearly enough to see if they are original type or reproduction items.
The steering wheel is late '60's/early '70s-on, usually Fiat 124, Fiat 850 & Abarth A112. The u-jointed steering column looks to be out of a Fiat 850, not 750GT; the steering knuckle/joint is visible thru the square hole to the right of the fuel tank.
As for the dash - it looks to me that the switch hole normally found to the left of the ignition switch was part of the dash sheetmetal that has been cut away to install the 850TC-style gauge unit. The hole (toggle switch) seen immediately to the right of your ignition switch is not original - it's most likely the left-hand switch relocated in a new spot. The switch on the far right is in the normal location. If you measure the gap between the ignition switch & the far right toggle switch, then flip it over to the left, that should give you the distance where the toggle should normally be on the left side (about on the edge of your gauge assembly). Your dash is also missing the padded upholstery piece that runs the width of the lower 1/3 edge of the dash (that what those little slot-holes are for, they're the mounting holes).
If your car was a true 750 Berlina, I'd say it is all but lost due to the previous owner's "upgrades" through the years. Sad to say, but you now have another 850TC clone like many others out there. Nice stuff on the car, but unfortunately not the "correct" assemblage of parts for either a 750 or an 850TC (or even a true replica of either). =(
I'll bet it revs nice, though! Just drive it & enjoy it. =)