As far as what I know and own, Griswold made these skillets in 3 sizes, 7, 8, and 9. As I was putting my iron back in place after some forced re-arrangement I was a little surprised to see a difference in the markings and handles on the 3 sizes. Knowing Griswold it shouldn't have surprised me that there were differences but still....
These skillets are around but they can be tough to find. I've seen one or two sizes on e-bay and I looked for quite a while to get the 9. FInally found it at an antique store, but probably passed up more than one early on in my skillet lifting carreer. Even though they are a lot less common than the regular Griswold skillets in this size, I don't think that is enough to command much of a premium price, if any. They are out there and a lot of folks just don't know what they have in their hands. The 3 digit pattern number will tell you what you are holding. On the iron mountain chrome skillets, I have never seen one in my travels, but if you saw one and the chrome looked original, then there are more than likely other sizes out there.
Harry