I dont think the rails on an F-16 will matter. I have flown 2 Avonds 16s with rails for several years. The problem may arise when you put missiles on them. On my first 16 I put scale AIM-9s on the rails which caused wing flutter and ultimately the loss of the airplane. The last time I checked, PA recommends his F16 not be flown with the external stores. In PAs defense he was excellent to work with following my loss. He put out an AD covering the problem and sent all owners a modification to prevent further losses. I have bought two more of his airplanes since then. Both are excellent flyers. We dont really check the loads placed on the wings with external stores and in some cases it may be bad news.