Congratulations on your new #1 - you will love it! As for the chicken, I don't know why the recipe calls for wrapping the bird. Perhaps because of the butter rub?
I have done several 5lb chickens in my #2 and I never wrap them and they come out very tasty every time. I use a dry rub, however. I would also recommend brining the chicken before smoking. If you do try wrapping, perhaps putting a few small holes in the top would help to get smoke on the chicken.
Related to wrapping, I tried wrapping baked potatoes and smoking and while I got some smoke flavor, it wasn't very strong. This past weekend I smoke the potatoes unwrapped for the first 2 hours, and then wrapped them for the remaining 2 hours -- what an improvement!