It refers to the shipping marks.

指船的标识表记标帜。

The second group stencilled the shipping marks.

第二组用模版印制装船唛头。

Cardboard cartons, with stenciled shipping marks.

李：刷有抬头的硬纸板箱。

Cardboard cartons, with stenciled shipping marks.

刷有抬头的硬纸板箱。

In no case should the shipping marks be misprinted.

以防万一运送标志不应该被印错吗。