I like to steam my fondant. I like the shine, or at least it being less dull after steaming.  I bought the Conair handheld wand type steamer- works GREAT- NO DRIPPING, like others I tried.  About $30 from Target. 

Anyway- for this cake- it's an early am delivery.  I have my bow made and dry. It's Thursday and delivery is Saturday am.  Should I steam it now?  Will the dullness stay away? I haven't done it with gum paste only fondant.

Thanks for your advice. 

This is a good question and I am also interested in knowing this. I hope you get a response.

So, I did it a few hrs later.  Turned out great.  Using gum paste this time, not fondant. Looked so much better- not dull , not shiny, even 2 days later when I put them on the cake.

I also did a test piece of gumpaste, steamed it and put int he refrigerator.  That too was fine. So I was confident to put my cake in the refrigerator ( cream cheese frosting) that had 2 ribbons of gumpaste across it. It was fine the next morning as were the decorations that I left out.

Another interesting event- I need to repair a gumpaste baby's head that was dented- I made it over a week ago. I took out the smallest piece of skin tone gumpaste, wet it slightly and smooth it into the dent last night. The dent filled but it wasn't smooth enough.  This am, I steamed it before I put on the cake and it looked great, but the time it dried ( with a little assist from a portable fan). Almost perfect smoothness, Met my standards to put on the cake. 

Good luck and steam away. Love it.