Ogriv,
I don't know about the GP kit, but I do know that the GP ARF Cub I have the wing supports are functional. Meaning they are there to help secure the wing on. You might want to ask around a bit and find out if you can safely leave them off, other wise you may want to put them on. It's a sick feeling to watch a wing come off a plane while it's in flight.

Hope this helps

Ken