Well 25-30 years ago in Texas I bought what airgas called lifetime lease bottles the carbon copy recipes are long gone.
In Texas and Arkansas I exchanged them no problem usually from the delivery truck when they were local to me.
They didn’t seem to care if the neck ring was marked or not , seems they do here in Cali I got my 75/25 exchanged here and they charged me again for the bottle, so I guess I’m screwed when I need gas. The Airco is a120cf oxygen , with Airco on the ring.