Clever way to check for sync-status

[FlxAlbroscheit]

This may be more a question than a feature request, but:
I shortly realized that this plugin automatically adds an ID (similar to "-KecHZh3...") to new models, so certain backbone-methods (such as model.isNew) may won't work anymore... Is there a clever, more native way to check whether a model/Firebase-collection has already been synchronized, such as model.synced()?! As of now you could reach such functionality by e.g. hooking into the sync-function, but that's not the best solution in terms of performance because changing a model's (pseudo-)attribute (like "synced") from false to true will result in another request... Any ideas, plans?