I believe the lumps started right after the clips were dropped in 61, not sure how long they lasted, but I remember mine came from a guy with a mid/late 70's truck

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