From various surviving artifacts there appears to have been a style of leather tooling that was used in the California missions and by leather workers throughout California in the Mexican era, some of whom may have been former neophytes.
There is a confssional preserved at Mission Santa Inez that has a tooled leather seat. From the fact that it was recorded in the 1930s by the Index of American Design, I believe it could date to Mexican era California. For those who might not know, the Index was a Depression-era government program meant to record significant cultural artifacts and to keep artists employed. Its images are available through the National Gallery website and, though the identifications are nearly useless (this confessional seat is described as a "carpet"), you can sort them by items from California.
What emerges are several pieces that seem to show a very consistent visual style that includes knots, parallel lines, diaper patterns, tear drops, and highly stylized flowers and foliage.
Unfortunately, the website tells us nothing about who owned the objects when they were recorded in the 1930s but I've been assured by the National Gallery's archivist that I can look through the records and try to pin that information down the next time I'm in Washington, D.C. (which will have to wait until next year).
The last image is one I've posted before, a mochila that I've been told dates from the 1850s. Nevertheless, I believe that the tooling displays many of the same decorative elements found on other leather objects connected with ante-gringo California.
People might be interested in using these design elements when recreating Californio artifacts, including saddles. I should note that the way the space is divided up on this mochila, with a "keyhole" in the center and more-or-less triangular shapes front and back is one that I've seen used as far back as Spanish Mexico.
A. Confessional, Mission Santa Inez, California
B. and C. Confessional seat, Mission Santa Inez
D. Confessional seat, Mission Santa Inez (Index of American Design)
E. Padre's sandal (Index of American Design)
F. Leather baptismal font cover (Index of American Design)
G. and H. Unidentified pieces of tooled leather (Index of American Design)
J. Mochila (Index of American Design)