In 1987 Fender opened the Mexican plant in Ensenada, which became operational and started to produce guitars only in 1990.
The serial number of the “Made in Mexico” Stratocasters, was located on the front of the headstock, is very simple and intuitive: it provides a suffix composed by the letter “M” and one indicating the decade (“N” for the 90s, “Z” from 2000 and “X” from 2010), followed by five or six numbers.
In 2010 also for the Mexican Stratocasters, as already happened for the American ones, a serial number without letters but composed by the prefix “10” followed by seven numbers was used for some months. In these cases the origin of the guitar was reported on a decal placed on the back of the headstock next to the serial.
Moreover in 2010 the serial number was moved on the back of the headstock of the Mexican Stratocasters.
Obviously, there are some exceptions, like the California Series, whose serial number was characterized by the prefix "AMXN", and some signature guitars, with the prefix "MS" + "N", "Z" or "X", according to the decade.
It is interesting to note that some of these, like the Jimmie Vaughan or the Buddy Guy Standard Stratocaster, had the serial number with the prefix "MSN" also if made in the 2000s (and not '90s as you might think). In these cases the real dating of the instrument has to be done by reading the other dates on body, neck, pickguard or thanks to the 1996 anniversary tags placed on the back of the headstock.
In addition, in October 2010 also Mexican signature strats moved to the serial number "MX10".
The serial number of the “Made in Mexico” Stratocasters, was located on the front of the headstock, is very simple and intuitive: it provides a suffix composed by the letter “M” and one indicating the decade (“N” for the 90s, “Z” from 2000 and “X” from 2010), followed by five or six numbers.
In 2010 also for the Mexican Stratocasters, as already happened for the American ones, a serial number without letters but composed by the prefix “10” followed by seven numbers was used for some months. In these cases the origin of the guitar was reported on a decal placed on the back of the headstock next to the serial.
Moreover in 2010 the serial number was moved on the back of the headstock of the Mexican Stratocasters.
Obviously, there are some exceptions, like the California Series, whose serial number was characterized by the prefix "AMXN", and some signature guitars, with the prefix "MS" + "N", "Z" or "X", according to the decade.
It is interesting to note that some of these, like the Jimmie Vaughan or the Buddy Guy Standard Stratocaster, had the serial number with the prefix "MSN" also if made in the 2000s (and not '90s as you might think). In these cases the real dating of the instrument has to be done by reading the other dates on body, neck, pickguard or thanks to the 1996 anniversary tags placed on the back of the headstock.
In addition, in October 2010 also Mexican signature strats moved to the serial number "MX10".
Tab.5 Mexican Stratocasters serial numbers
1990

MN0 + 5 or 6 digits

1991

MN1 + 5 or 6 digits
A few MN0 + 5 or 6 digits 
1992

MN2 + 5 or 6 digits
A few MN1 + 5 or 6 digits 
1993

MN3 + 5 or 6 digits
A few MN2 + 5 or 6 digits 
1994

MN4 + 5 or 6 digits
A few MN3 + 5 or 6 digits 
1995

MN5 + 5 or 6 digits
A few MN4 + 5 or 6 digits 
1996

MN6 + 5 or 6 digits
A few MN5 + 5 or 6 digits 
1997

MN7 + 5 or 6 digits
A few MN6 + 5 or 6 digits 
1998

MN8 + 5 or 6 digits
A few MN7 + 5 or 6 digits 
1999

MN9 + 5 or 6 digits
A few MN8 + 5 or 6 digits 
2000

MZ0 + 5 or 6 digits
A few MN9 + 5 or 6 digits 
2001

MZ1 + 5 or 6 digits
A few MZ0 + 5 or 6 digits 
2002

MZ2 + 5 or 6 digits
A few MZ1 + 5 or 6 digits 
2003

MZ3 + 5 or 6 digits
A few MZ2 + 5 or 6 digits 
2004

MZ4 + 5 or 6 digits
A few MZ3 + 5 or 6 digits 
2005

MZ5 + 5 or 6 digits
A few MZ4 + 5 or 6 digits 
2006

MZ6 + 5 or 6 digits
A few MZ5 + 5 or 6 digits 
2007

MZ7 + 5 or 6 digits
A few MZ6 + 5 or 6 digits 
2008

MZ8 + 5 or 6 digits
A few MZ7 + 5 or 6 digits 
2009

MZ9 + 5 or 6 digits
A few MZ8 + 5 or 6 digits 
2010

MX10 + 6 digits
10 + 6 or 7 digits A few MZ9 + 5 or 6 digits 
2011

MX11 + 6 digits
A few MX10 + 6 digits 
2012

MX12 + 6 digits
A few MX11 + 6 digits 
2013

MX13 + 6 digits
A few MX12 + 6 digits 
2014

MX14 + 6 digits
A few MX13 + 6 digits 
...And so on