Ancestry has partnered with the Mormons to include many Italian records.
When the Mormons did their filming in Italy they negotiated with the State Archives. Most, but not all, cooperated. Salerno was one who did not permit filming. Salerno was another.
To get records back to about 1809 you can write to the State Archives in Salerno. After 1865 write to the individual town or city and request them.