Could've had an old cleaning and then retoned. The luster on the reverse is much richer. None of the little circulation marks of an AU (that I can see from photos), so I suppose MS is the right grade. Go worn dies
San Francisco Walkers are notorious for weak strikes, especially in the 40s. I don't think I have ever seen Liberty's left hand on a 40s San Francisco Walker. Do they exist? Probably, but they are rare.
Again, another slider, I do not remember if they used AU-58 regularly then or not, but I will say AU-58 jim