Kurt - "TF" is what ya got - 55 2nd to 59 is the "Task Force era" [Chevys sales hype] - the 'apache' part started in 58 and applied to any
light truck [31,32,36,38 series] whereas the 'mid size' 40 and 60 series were called Vikings, and the heavy weights [21,000 gvw +] were called Spartans
I have guys ask sometimes "that's an apache, isn't it?" when I'm drivin the 57, as if that makes it deelux, or not a chevy

"I say no, it's a pickup truck!"
Bill