They look similar to the wide rally arches fitted to the Mirafiori 131 TC models. More likely they're not specific to the Uno but instead have been adapted from another model?
Just had a quick search and they are totally different to the 131 Abarth arches They're much more rounded for a start! See pic below.
They do remind me of that wide arch project Punto that appeared on the forum a while back (got flamed to buggery!) and never got finished. The thread for it is here but all the pics have gone because of an inactive photobucket account. Shame as they were a bit, erm, interesting (*snigger*) to say the least!