Oh wow - thanks so much for all the quick responses. After reading them all it appears that all are correct and in fact what was happening is exactly as unixrevolution described. The inner numbered-dial was indeed spinning and along with the outer ring being able to turn it was causing me the confusion. I was able to snug it up a little with just my thumb and pressing/rotating it. But now I want to compare it to other photo examples of a GSN to make sure when I finally snug it down with a small spanner it will be in the correct final position. Otherwise I'll turn the dial to the incorrect place, right? At least that is how I think about it in my head. For example if I turn the inner dial too far when snugging it down, then ISO 400 could actually be one or two notches too early on the dial. Either way thanks again all of you for helping clear it up for me.