Baja California Sur does not border the USA, but it does issue a Fronteriza plate. 

The Fronteriza plates were introduced in 1972 and are available in the Mexico–United States border zone. This zone is formed by the states of Baja California and Baja California Sur, as well as parts of Sonora, Chihuahua, Coahuila and Tamaulipas. While the state of Nuevo León shares a 15-kilometre (9.3 mi) border with the U.S., it does not have any cities within the border zone. The Fronteriza plates are to be used on foreign vehicles that are imported into Mexico, so that they can be registered and driven within Mexico without having to go through the corresponding legal import procedures. However, these vehicles can drive around only within the border zone. 

Baja California Sur issues Fronteriza plates because there are automobile ferries to the mainland.  The Baja states have always acted more like an island than a peninsula.  People here in BCS call the rest of Mexico the mainland.  

Baja California Sur issued its current base plate design in 2022, and it features a gradient color band at the top with the state map and other identifiers.  From 2022 through 2025, but discontinued in 2026, the plates also have Delantra and Trasera plate decals for front and back.  

While the passenger series has dark green gradient banner at the top, the Fronteriza (with the word “FRONT” at under the top left bolthole).  The majority of the Fronteriza plates have a dark purple gradient banner at the top.  But there are some examples (may 5-10%) that have a light brown gradient design instead.  At first, it looks like they may be  a faded version of the dark purple, but upon closer inspection it does appear like a completely different and clearly muted gradident banner.   What’s your opinion?