"we wonder why in general it takes decades to even know what the correct interior and exterior looks like on a 105 car"
True, as there have been many different iterations, and owners through the years have traded interiors around in different cars, so that we lose track of what was in the original configs for that.
For instance, my red 64 Sprint GT from new had a medium blue vinyl seat material but light blue cloth in the center sections, both seat cushion and back. The door cards were also the medium blue vinyl. I have never seen that combination anywhere, here or in the museum. It was very nice, better looking and wearing than what I've seen in later cars.
1989 Milano, Shankle Sport
1991 164S, stock
1994 164LS (~Q)
1972 Morgan 27
previously owned since 1964:
62 Morris MiniMinor 850, 67 Austin 1275 Cooper S (Downton 3/4 race), 64 Giulia Sprint GT (1st red one made), 72 Fiat 128 Sedan, 75 Alfetta Sedan, 78 Alfetta Sedan, 78 GTV, 81 GTV6, 86 GTV6