I would guess that the conjunction of Fierro and Perales in my name are merely coincidence, as relates to your query, but here goes. The Perales in my family are from Durango. My granfather Antonio Perales was a vaquero and also a butcher there. He mentioned to me having known Hipolito Villa, Pancho Villas brother. My grandfather was a spy for the revolutionarys and was forced to flee to the border. My father Juan Francisco was born 1918 in Mexico near El Paso.The family settled in Riverside California. Antonio Perales wife, my grandmother was Juana Rivas, reputedly of the landed gentry. A cousin relates to me that Antonio Perales fell into a well and was there three days before being rescued. Juana nursed him to health and they fell in love.As for the Fierros you might try Dr. Brondo Whitt's book (for starters) LOS PATRIARCOS DEL PAPIGOCHI. It is a very thorough geneology of the Ciudad Guerrero area west of Ciudad Chihuahua and contains all of the old founding families of that area. I have Fierro cousins there. Also LuzCorral Fierro, born in San Andres Chihhuahua in 1892, was Pancho Villas wife(recognised as such by President Obregon after Villas assasination), she maintained Villas home in Chihuahua antil her death in 1981. If you encounter Fierros related to her then you are onto my family and I will be happy to share what I know, which is a fair amount. Good luck.