I'm not sure where you can get the info.... But you would need to find out if these are actually one step colder for your Fozzy or not. There is a chart somewhere I'm sure. Even though these plugs can be had at NAPA, don't bother ask them, they wont know what you're talking about.
They may screw in just fine. But they might not be once step colder.
But $20 is a really good deal. Typically they will run you in the area of nearly $40 for the set. And yes they are new, I talked to Mark about them a while back.