It is probably a Western Marshall, these are the most common encountered. All the ejector rods should fit, as well as one from a Ruger, Colt, Uberti. I would suggest that if you are going to use it much you look at one from another source. The Sauer ones are not very robust, the button you push (for lack of a better term) is made of the same pot metal as the back strap/ trigger guard, and prone to snap off.
Here is a source for a lot of the Italian repro parts: http://www.vtigunparts.com/
You could also look to Brownells for the aftermarket parts for Rugers, I think Belt Mountain is the maker.