TZ maintains for zone America/Tijuana that there was not DST observed between 1961 and 1975.

# Baja California
Zone America/Tijuana    -7:48:04 -      LMT     1922 Jan  1  7:00u
                        -7:00   -       MST     1924
                        -8:00   -       PST     1927 Jun 10
                        -7:00   -       MST     1930 Nov 15
                        -8:00   -       PST     1931 Apr  1
                        -8:00   1:00    PDT     1931 Sep 30
                        -8:00   -       PST     1942 Apr 24
                        -8:00   1:00    PWT     1945 Aug 14 23:00u
                        -8:00   1:00    PPT     1945 Nov 15 # Peace
                        -8:00   -       PST     1948 Apr  5
                        -8:00   1:00    PDT     1949 Jan 14
                        -8:00   -       PST     1950 May  1
                        -8:00   1:00    PDT     1950 Sep 24
                        -8:00   -       PST     1951 Apr 29  2:00
                        -8:00   1:00    PDT     1951 Sep 30  2:00
                        -8:00   -       PST     1952 Apr 27  2:00
                        -8:00   1:00    PDT     1952 Sep 28  2:00
                        -8:00   -       PST     1954
                        -8:00   CA      P%sT    1961
                        -8:00   -       PST     1976
                        -8:00   US      P%sT    1996
                        -8:00   Mexico  P%sT    2001
                        -8:00   US      P%sT    2002 Feb 20
                        -8:00   Mexico  P%sT    2010
                        -8:00   US      P%sT

A user of our astrology service, born in 1973 in he border town Mexicali claimed that
they observed DST in his town, just like on the other side of the border in California, when he was
born on 30 May 1973.

I did a quick newspaper archive research  on https://hndm.iib.unam.mx/
and found that 

Título:
Periódico Oficial del Estado de Baja California Norte
Fecha:
1973-04-20

states clearly that DST was observed from last Sunday in April to last Sunday in October.

This means the the TZ table above is false, at least for 1973.
I assume that the same is the case for several other years.

I attach the screenshot for 1973

The page https://hndm.iib.unam.mx/consulta/publicacion/visualizar/558075be7d1e63c9fea1a3b2?pagina=558a34887d1ed64f16a710da&coleccion= should allow to search for other years as well.

I used the keywords hora legal for my search, though  do not see that now in the URL.