I'd guess that if you've found the same identical 'notch' on 12 different cabs, then it's a pretty safe bet it was factory, or they've all been thru the same body shop for the same 'modification' grin

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