Semi-long answer.
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.