Welcome to Gente Jamie-Ray. I believe the correct surname spelling is Rocci
sano as I am currently in touch with several people from Caulonia with that surname.
You may request a copy of your grandfathers birth certificate (or birth act is a longer more detail copy of the original as opposed to an extract) directly from the Comune di Caulonia or from Family Search.org
since you already have a birth date to go by.
You can use the link below and request the copy by filling out the form and using this information:
Nati 1901 FHL INTL Film
1880623 Item 2
They do require a small fee for the look up but there is also a toll free number on the form which you can call (from the USA or Canada only I believe) for more information or help. I have called them a few times and find them very helpful.
Hope this helps.