Hello Dave,
My precut kit was supplied by PCK. Yes the wing did come with the holes precut for the tube. I dont believe the plans show a 2 piece wing for the P47 but if you take a look over on RC Scalebuilder theres a guy who has just modified his own to a 2 piece wing. Please see link.
http://www.rcscalebuilder.com/forum/...41&PN=1&TPN=29
I have the plans and accessories for the 1/5 Ziroli P47 as this is my next build, I too intend to use Sierra for the retracts, great gear.