WP might have caused that damage, or it might have been simple high speed impact.
Steel has a certain degree of "plasticity, and will deform under a high speed impact, leaving a melted looking result. Also, I'm pretty sure that same impact results in a significant amount of heat, for a very brief moment of time.
If you look at armored vehicles (tanks, etc.) from WWII, which were struck by SOLID anti tank shot (steel on steel) you see very similar looking results.
Shrapnel is a widely misused term, commonly used today for any and all shell fragments.
Growing up, one of my neighbors had been a paratrooper, who survived the Normandy drop on St. Mere Eglise, AND the Battle of the Bulge at Bastogne.
Great guy, who never talked about what happened, other than to say he was there. When the movie The Longest Day came on TV, his wife said he watched about half of it and went to bed. He had nightmares for weeks afterwards, she said.
He's long passed now, his friends still miss him, I can only imagine what he would have relived if he had lived to see Saving Private Ryan...