Well Stig,
I believe we've gone as far as we can go on French operated, Italian built Capronis until further information,documentation or photos with SFA numbers outside those already alloted for CEP machines. As things stand we definitely appear to have aircraft,but even more definitely no known serials.
Here are some photos recently posted on ebay showing that it was in fact possible to put serials on your Capronis,albeit the sellers captions are a bit off with regard to types of Caproni shown
https://www.ebay.it/sch/i.html?_dkr=...aproni&_sop=10
Regards,
Clint