Bob,
You really should have the Western Cover Society's June 2010 edition of their publication "Western Express". The edition I am talking about covers Hidalgo Express and the Wells Fargo & Co. Express in Mexico. It is an amazing work put together by Dr. Robert Chandler, the current president of the society. I understand you can purchase this from them or join for $35 a year and get a copy, but you should contact them regarding this.
Their web site is
www.westerncoversociety.com Contact information for membership is
Western Cover Society
John Drew, Secretary
15370 Skyview Terrace
San Jose CA 95132-3042
USA
email address JandNDrew@aol.com
If you have any questions, these people would be the first to contact.
Bubba