To me, it's Dark Munich malt that makes a Dunkel taste like a Dunkel. It has this really dark bread crust character that I just don't get from any other malt. To me, I think a Dunkel made primarily with Light Munich would end up closer to an Ofest in flavor.
I agree with Keith completely, the Special B is way out of place here - unless by "imported age" you mean "sweet fig and raisin". I like Special B, but not in lagers.