Native Mexican vs. Spanish Mexican surnames?

Does anyone know where I can find records or information on how names were given in Mexico? I know a lot of Mexican names are found in Spain, so presumably people with a Rodriguez or Sanchez surname have that Spanish ancestry? But what about the native Mexicans? I can't imagine the Spaniards giving them real Spanish surnames because of the racial discrimination towards them, so were they given other names, what were they? Is there a way to tell? I know Mexican's are so mixed now that some people who are mostly Native might be a Garcia for instance, only because they have one spanish ancestor out of many natives. Any insight here? I'm looking for real sources here, books, articles, preferably.