Oh...I had forgotten.
YES.
You are right!
I forgot it too, lol. Carl seems to have mellowed since then. For a while there he seemed to be trying to out "Rick" Rick. But I still say he was right to shoot this kid.
Look at those eyes, darting back and forth between Herschel (a one-legged old man) and Carl (a boy holding a gun that's almost heavier than he was). He was going to try something and Carl knew it.