The dual pane windows are tinted, although they are not as dark as the single pane.
I got this today from a trusted source from Keystone. The R-value is less than 2 between the single and dual pane windows. Dual pane windows provide a much better sound insulation compared to the single pane. Their quote was "if you want less sound in your coach, go w/ the dual pane. Be ready for the trade off, weight and cost." "Not much better than single pane as far as temp control goes."
Thought I would pass that along.
2004 Chevy Silverado LT 2500HD CrewCab Duramax
2004 Montana 3400RL