Dictionaries are fairly flexible. For example, you could include the sprite's path inside the dictionary as a property. Or, you could include it as the key in a dictionary of dictionaries.
The first would look something like this:
var item1 = {"path": $Sprite.get_path(), "weight": 50, "durability": 75, "protection": 100}
The second would look something like this:
var items = {
$Sprite.get_path() : {"weight": 50, "durability": 75, protection": 100},
$Sprite2.get_path() : {"weight": 40, "durability": 55, protection": 80}
}
For that second item, you could retrieve the info for a give sprite via:
items[$Sprite.get_path()].weight # for example