Yeah, that's what I'm talking about. In the earlier AD trucks there was a little tab as you describe. On my '56 its a raised grab area around the key. I'm assuming the '57 is the same.

"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.