s ▁of ▁General ▁Mot ors ' ▁vehicles ▁beginning ▁in ▁ 1 9 6 6 . ▁This ▁logo ▁also ▁was ▁stamp ed ▁on ▁the ▁release ▁buttons ▁of ▁seat ▁bel t ▁bu ck les ▁on ▁G M ▁vehicles ▁from ▁ 1 9 6 7 ▁until ▁ 1 9 9 6 , ▁as ▁well ▁as ▁being ▁stamp ed ▁onto ▁the ▁ign ition ▁and ▁door ▁keys ▁from ▁ 1 9 6 9 ▁up ▁until ▁ 2 0 0 2 . ▁Origin ally ▁tur qu o ise , ▁the ▁color ▁was ▁changed ▁to ▁a ▁royal ▁blue ▁in ▁ 1 9 6 8 . ▁ ▁The ▁" Mark ▁of ▁Ex cell ence " ▁was ▁the ▁subject ▁of ▁the ▁first ▁case ▁considered ▁by ▁the ▁National ▁Ad vert ising ▁Review ▁Board , ▁in ▁ 1 9 7 2 ; ▁ ▁The ▁N AR B ▁ruled ▁that ▁the ▁mark ▁was ▁not ▁being ▁used ▁in ▁a ▁manner ▁that ▁constit uted ▁false ▁advert ising , ▁but ▁war ned ▁that , ▁given ▁G M ' s ▁record ▁of ▁product ▁rec alls , ▁ ▁the ▁s log an ▁could ▁be ▁seen ▁as ▁de cept ive ▁if ▁it ▁became ▁a ▁primary ▁theme ▁of ▁G M ' s ▁auto ▁advert ising . ▁ ▁The ▁phrase ▁" Mark ▁of ▁Ex cell ence " ▁and ▁its ▁appearance ▁on ▁the ▁logo ▁was ▁ph ased ▁out ▁by ▁the ▁ 1 9 8 0 s . ▁ ▁In ▁ 2 0 0 5 , ▁it ▁was ▁announced ▁that ▁small ▁silver ▁em blem s ▁of ▁the ▁logo ▁would ▁be ▁applied ▁to ▁the ▁exterior ▁of