The price for a pair of shoes and corrected grain isn't always correlated. Corrected grain leather doesn't always mean it is bad, bad is all about the tannage. So, would SM use corrected grain leather? I don't know, it depends on this finish they are going for. Church does, but their leather is good. They offer the same shoes in non-corrected for the same price. People own both kinds for years and years.
As for the pebble, or scotch grain, it is a "kind" of correction. I would guess 99.9% of all scotch grained leathers on shoes today are stamped with the pattern of the grain. Apparently back in the day the leather was soaked in scotch to shrink it and give it the grained look. Isshinryu might know something about it more than I would as he is up on old shoes. Even further as the bootmaker DWFII.