I am going to disagree here, but I am going to go from memory because all my documentation is in Texas, 1100 miles away.
The AT-84 was the first version of a CZ clone made by Solothurn in Solothurn Switzerland, later modified and again imported as the AT-88. The 84 corresponds to the year 1984 and 88, 1988, as the years the designs went into production. They were imported by Action Arms who was also the importer of the Uzi and Galil at the time. They were very high grade for a copy yet I believe that the guns, although made in Switzerland, were on Tangfolio castings. The EAA guns are assembled here on Tangfolio castings, but enter the U.S. as complete frames. I believe the Swiss guns also have hardness marks on the frame and slide, as do CZ's, that would lead me to believe that the bare castings were finish machined by the Swiss company. That may not be the case as Swiss firearm and import laws are different from those in the U.S. so they could have been using the Italian machined castings, possibly just heat treating or just doing the hardness test themselves. Though the Sphinx pistol is similar and comes from the same factory, Sphinx is a British company who contracted out the production of the gun just as what we know as a Browning High Power in not made by Browning in Utah, but by FN for them in Belgium.
The pistol was not offered in stainless and all the pistols I saw, whether plain or fancy, were all blue. It is a good pistol, to me in EXCELLENT (95%+) condition it should bring around $300. Remember that you can buy a NIB real CZ-75 for around $329 and it would surely NOT be worth more than that.