Don't know when they changed to the aluminum backs, but I would guess after ' 78, when all the originals were gone. Here is a list of the different slogans that were used through the years, and many were license plates.
*Count On Chevrolet to Build the one you want
*The Great Highway performers
*more,more,more for 64
*Chevys Lateset,Chevys Greatest!
*There's 5 in 64
*Roll Chevy Roll!(NSC)
*Something New For EveryBody!
*The Beautiful Shapes for 65!
*Buy Word For '65..by Chevrolet
*65's Beautiful Breakaway (or Breakthrough) by Chevrolet
*The MAKE that MAKES you want a 65!
*Red Hot and Rolling!(NSC Campaign)
*Here and Wow!
*Steer em right!(NSC)
*New and Great!
*The Super 65's
*A perfectly beautiful year to Go Chevrolet
*Your year to live it up in style
*Thrill of the Year
*Double divendend days!
*The thrilling 66's
*High Style! New Spirit!
*Everything new that could happen...HAPPENED!
*Rumors come true Wonderfully!
*Mean more than ever before
*Exciting Beauty! Power that moves!
*Always out front in safety,(or styling)
*Chevy comes out swinging for 67
*America's No.1 Seller
*Look at Chevrolets Latest!
*Decidely 68! Chevrolet!
*Stunningly Beautiful! Superbly Built! The 68 Chevrolet! Dramatically Designed! Distinctively Different! Daringly New!
*Putting You first Keeps Us First!-(USA-1 License plate slogan too)
*The Leader Comes on Strong
*"On The Move" The Chevrolet 70's.
*See America's First-(License Plate Slogan)
*The Chevrolet Movers (Trucks)
*Putting you first in a Big Way-(license Plate slogan)
*Totally Tougher (Trucks)
*The Little Car that Does everything Well (Vega)
*For you in 72!
*We want your Chevrolet to be the best car you've ever owned.
*Totally tougher to last longer (Trucks)
*Building a Better Way to See the USA (Mid year Red-White-Blue Motiff License Plate Slogan)Used in 1974 also
1973-Red-White-Blue motiff takes off.
*Building a Better Way to Serve the USA (Trucks)
*Chevrolet Makes sense For America
*Lasting Chevy Value (Trucks)
*America's favorites,BaseBall,HotDogs,Apple Pie and Chevrolet (used well into the 76- 77 years too)