Trapperready, that may have been me. I don't remember if I posted about it on THR but I spent $10 to find out that apparently whatever differences there are between the recievers of the Gold and the SX2, they're enough that a shell catcher for a Gold definitely won't work for an SX2. That being said, asside from asthetics (nicer fit and finish on the Gold), the guns are pretty much functionally identical. I read an article when I first got my gun comparing the two and the gas systems and performance were basically identical.
www.tommortonandcompany.com sells a mechanical shell catcher for Remingtons that can be used for doubles. It's a little pricy, but it looks like a pretty cool device. They're developing them for the 390, SX1, and SX2. I have one of their mechanical recoil reducers that I like a lot and plan on buying the shell catcher when it becomes available. I'll email them and let you guys know when they expect to start selling the shell catchers. From another thread, there seems to be a significant number of SX2/beretta owners on this site. Maybe they'd do a group buy?