Well it looks like the toolbar icon always defaults to the first icon in the library. The context menu item Open
gets the one specified in the registry. As of right now, I've decided on this one "explorer.exe,-251
". The explorer icon in the toolbar makes more sense to me than flip 3d.
However, I did manage to hack it another way. I used an old and very small .exe file, stripped out the code leaving nothing but the icon resources and came up with this to get the same icon for both locations.
More than likely, I'm leaving it the default Mickey Soft Doofus way since hovering .dll files and maybe some others would need tweaking as well to get rid of the generic icon