It seems like you should be able to but this didn't work for me. myStore is a jsId.

dojo.connect(myStore, "onItem", function() { console.log("item") });

Sorry that's a pretty vague subject. What I have is a store of items like this:

items: 
[
  { name: "button", category: "core", imageSrc: "image.png", label: "Button", description: "It's a button!" }, 
  and repeat...
]