The link goes to the weber site and a question about ribs on a smoker.
But to answer your question otherwise, it depends. If the label on the cherries in the store doesn't say, ask the produce manager what kind they are. Cherries here in upstate NY are now ripe for picking and the orchards often offer both sweet cherries and sour. Your market may offer both and if you have an orchard near you, I recommend picking your own.
I suspect the ones in the market are typically sweet cherries because those are most often eaten as is while sour ones are great for pies, preserves, etc but usually need some sugar added. So if the recipe calls for sour cherries, make sure you get sour cherries. Or cut back on the sugar in the recipe.