If you buy just the Avistar, it came with a wood dihedral brace (wing-joiner) The guys who bought the whole kit (radio, engine etc) had those metal rods at each end; though as far as I recall, there was also a dihedral brace (piece of plywood about 6 inches long like a really open V. You have to epoxy two pieces together to make it thicker.

The metal rods weren't in the new kit I build for my buddy though it's possible all the newer kits have them now.

Just remember, despite what seems to be in the instructions, don't just bolt on the tail surfaces, use some epoxy

Bob