Are over carbed darker beers more noticeable?

Since getting my kegging setup, I've mostly made lighter beers, Wits, Hefes, pale ales. I've kegged 2 darker beers, a Nut Brown Ale and a Scottish Ale. Both of these got slightly over carbed and I noticed a definite sour bite to them that would go away if I agitated them to degas them. Is my assumption correct that lighter beers a little more forgiving if they get overcarbed? And was the off taste I picked up definitely from having a little too much CO2 in solution?

Yes, I've had this happen too. Typically the harshness I tasted from from the darker malts (Astringent Bitterness). Over-carbonation can cause certain flavors to be accentuated.