In the past many Open models and Advanced models at the NATS used wings built by someone other than the competitor.
Which was legal at the time, and legal now (specifically called out).
Dennis and his cohorts have been using this "but someone used a Bobby Hunt wing!!!!!" for the last 10-15 years to incorrectly claim that "everybody was cheating" as a way to argue against BOM. It was never illegal. MOST of the arguing about BOM has been about such strawman claims.