I’ve just been trying to buy a few hundred pallets and confusingly there seems to be licensed pallets and unlicensed pallets.
A licensed (or stamped) pallet is a pallet that has been made to a particular specification and is guaranteed to carry 1 ton. All licensed pallets are made in the same way, using the same thickness wood, the same number of planks, the same type of nails etc etc.
An unlicensed pallet will fit the size specifications but cannot be guaranteed to hold a ton. You can send an unlicensed pallet through a carrier (pallet network) no problem.