Do VCI products have an active side?

There are 2 types of VCI paper: double-faced paper, impregnated on both sides, or one-sided PE coated paper. This latter is active only on one side, while the other consists of a barrier film able to keep the VCI within the package.
VCI film is always active on one-side.
On both VCI paper and film the active side (to be oriented toward the metal) is easily distinguishable, as it is opposite to the printed side.