The first edition of Mexico has no letter code. © Copyright 1969 by Western Publishing Company, Inc. Published by Golden Press, New York, N.Y. Cover price is $1.95. The number on the spine is 24022. Listed as a Golden Regional Guide.
Shown next is the Spanish version. Published by Ediciones Daimon, Manuel Tamayo. The copyright page states-
Printed in Spain
Publicationes Reunidas S. A.
© 1969 por Western Publishing Company, Inc. Dated 1973.
No revised edition or cover variant exists that I am aware of. Out of print.