Hi Greentip,
I thought you already had your trip to Italy.
I checked out the websites of the guns shops you listed. Honestly I don't know any of them, I live too far from Rome and I've never had the chance to go and visit them. I think that if you have the possibility to have a look you must do it. Every guns shop can have something interesting in stock. Looking at the websites I think that maybe Dragone could be the more tactical oriented between the two you said are the nearest.
Talking about Spas-12 parts, what are you looking for? In my opinion it's difficult to find something in stock directly in a gun shop. Franchi is here in Italy so gun shop owners often order parts directly from the manifacturer. If you are looking for some parts I can try to find them for you through my local gun shop and deliver them to your hotel in Rome. I give you another advice: the best gun shops in Italy are often located in northern Italy (where we have the greater part of guns manufacturers) and Tuscany. Tuscany is not far from Rome but honestly I don't know if you are going to rent a car here or not.
O.T. Did you receive my pm about swithcblades? I ask you because I never understand if my messages reach the recipient or not