I made a gum paste rocket ship plaque but I did not add a stick or wire to have it stand on top of my cake how can I add a stick to have it stand on top, the plaque is already hard would I mess it up if I used royal icing to glue the stick on back of my rocket ship let it hard and then top my cake with it?  Any help will be appreciated.

Molly2 

Since the plaque is already hard, I would do just as you said and glue the stick to the back. It will not mess it up at all.