USMC match rifles used the "meat tenderizer" buttplate...looks like Calfed has one of those with wider and deeper checkering than the one in the OP.
I think the story was in Canfield's book? - USMC recommended the whole Corps adopt these based on performance by the marksmanship team, and because there were not enough to go around armorers/individuals started to stipple the buttplates. I've read too much. Can't keep it all straight anymore. Correct me if I'm wrong on the source.