Flagging simulated data

Consider a typical list app, written in Meteor. When a user adds a new item to the list, Meteor will run its method on the client and the server to enable the ui to update very quickly. Is there a way of telling whether an item in the list is simulated, client-side data or data that has been successfully stored server-side?

My use case in this example would be to apply a different styling to new list items until they had been ran server-side. What’s the best way of achieving a different appearance depending on the status of the data in question?

Many thanks.