I agree. It looks like corking. I've read it's a way of putting up extra "armor" and making itself more sturdy. I think many cacti do this naturally as they age as well, to support their bulk. All my big, mature golden barrels are corking around their bases to hold that hefty body up!
That first picture, however, doesn't look like corking but a few spots of mechanical damage....probably got a little frostbit from the freezing temps.