The CRG site has the info below however did not have the First Edition part number. I have an original 1968 , Aug/1967 manual and it has part number 3927528. I figured you may want this for your records.
Kev

· 1968 Owner's Manual, PN 3xxxxxx
Camaro, Chevelle, Chevy II
Chevrolet Motor Division
General Motors Corporation
first edition, Aug 1967

· 1968 Owner's Manual, PN 3940153
Camaro, Chevelle, Chevy II
Chevrolet Motor Division
General Motors Corporation
second edition, Nov 1967

· 1968 Owner's Manual, P/N 3955532
Camaro, Chevelle, Chevy II
Chevrolet Motor Division
General Motors Corporation
third edition, May 68

Thanks. :)