Alfa part numbers are actually groups of numbers with each group having a specific meaning. The above example would be written 105.20.00.200.00. Here, we are interested in the 3rd group of numbers which identifies the parts group into which a part is assigned. Rotating valve gear, such a cams, are in parts group 03. So the part number above, with 00 as the parts group, would not appear to be a valid camshaft part number.
If the parts group number does turn out to be 03, this would be a USA version Spica cam used from 1972-1979 inclusive.
I happened to have just taken a picture of my cam over the weekend while I was scraping out gobs of sludge with a popsicle stick from underneath my cams! Who knows how long the car has been sitting. Anyway, its correct for my car, a 73 spider 2000 USA with Spica. That's probably what you have.
I hope the markings show up in the close up photo of the third, fourth and fifth numbers... stamped above and between the second and sixth numbers. And the last zero stamped on the end.