You guys ready for the answer... ?
The Screw in question under the top lever of 6 frame guns is to hold in an extension piece for the top lever linkage to fit into. The smaller frame sizes has a cut in the frame for this purpose. But, on the 6 frame guns, it is too large to use the normal top lever parts. So, instead of making all new top lever parts for just the 6 frame, they made up the extension block for the normal parts to fit into. So that way they could utilize the normal size linkage parts in the big frame.
Here is a photo of a 6 frame on top and a 2 frame on bottom. You can see the extension block attached to the bottom of the tang on the top frame.
IMG_3317.jpg
Hybrid Mode