You'd see a greater difference with a harder shot type (steel or tungsten), but not wildly different.
That lead shot deforms a LOT when it strikes the hard(er) surface so there's not enough energy left to give back to the angle of departure.
Mythbusters had a similar conclusion when they were using a handgun to bounce a round off 2 surfaces. Their second surface didn't do much beyond grazing the plate to "redirect" the bullet.
I remember discussing this topic with my brother who is now retired LEO. Recounted that at the academy they were taught to stand towards the middle of an alley and away from the sides for just this reason. They also did some firing drills with targets opposing them positioned along the walls to demonstrate the parallel flight of the bullet along the wall.