I've never seen a TF step bed with any beading behind the fenders

the reason your truck didn't have beading on the step joint is there wasn't any used - got an assembly manual? section 1 sheet 144 shows not any used on the fender to bedside either, just "underbody protective coating [6.5oz] - 1/8 bead entire length of joint"

Bill

Moved over to the Passing Lane

"When we tug a single thing in nature we find it attached to the rest of the world" John Muir
"When we tug a single thing on an old truck, we find it falls off" me
Some TF series details & TF heater pics & Rust-a-holics Unanimous parking lot