One of my sources indicates that IGA is the current importer for these guns. It also says that the best info available is from the older Stoeger catalogs if it is an older model.. Stoeger Industries inc. was purchased by Beretta Holding of Italy in 2000, and is now a division of Benelli USA.
I have not been able to find any rference to a Zephyr model either, with the Uplander models being easy to run down. I personally own one in 28 ga. SxS, and is one of my favorite grouse guns.
I would be interested to know what you find out.