That's one way to do it. However, you can use groups to name the objects you want to save, that way you don't have to make their names numbers. For example, on the objects, click the node tab on the top right under groups, and name it "Savable". Each "Savable" object will have the same function called "save_data()" and in that function, you call the autoload dictionary and save just the data for that specific object. Then to save everything you can do something like this:
var save_nodes = get_tree().get_nodes_in_group("Savable")
for save_node in save_nodes:
save_node.save_data()
