OSHA does not require weight marked on the container. That would be a sales information since items are sold by weight or by size. If you do this regularly, you can specify to your supplier that containers must be so marked. OSHA does require the rigger, person using a hoist, to know the weight of the load.
OSHA does require that all hoists to be so marked with capacity, so the rigger knows the limits of the machine, without having to go look it up in the manual everytime (which no macho man ever does).