The only ones I've ever seen and the only one I ever bagged, and it was only one, was around 40 years ago just off of Highway 15 about halfway between 138 and the summit. There used to be a dirt road that you could turn off onto from right off the southbound side of the freeway and then you'd follow the Edison tower roads around a hill and up a valley off to the west. I'm pretty sure they blocked off access to that road years ago. I did look at the San Bernardino County shooting map and that area appears to still allow shooting for "lawful hunting only". I chased them around for a couple of hours, got an occasional shot at birds the flushed at the edge of outside of range and finally had one the held and flushed almost right at my feet. I was going to have it mounted but due to the close range I blew the heck out of it. Went back there several times but never saw the mountain quail there again.