The 1958/59 Sinaloa private regular issue passenger plate is affixed to a diplomatic frame.  The Servicio Consular backing is fiberboard with a silkscreened front.

The red, white, and blue stripes suggest that this plate could have been issued to a foreign diplomatic outpost in the state.  The plate is most likely from the USA Consular office.  Even today in 2026, the USA has a consular office at Mazatlán on Playa Gaviotas in Zona Dorada.  Historically, Spain maintains a consular office in Los Mochis and Canada has an office in Mazatlán, too.

There are no other readily available records for other countries with a blue, white, and red flag having consular offices in Sinaloa, such as France, Cuba, Costa Rica, or the Dominican Republic among others.