Heading 480240 covers paper that has not yet received its decorative surface — it is an intermediate substrate sold to wallcovering manufacturers for subsequent printing, embossing, or coating. Heading 4814 covers finished wallpaper and similar wall coverings that already bear a decorative surface treatment. If the imported paper has any decorative printing, embossing, or surface coating applied, it is likely to be classified under 4814 rather than 480240, and importers should document the product's uncoated, undecorated condition at the time of entry.

Yes — wallpaper base is distinguished by its intended use and physical characteristics: it is typically heavier and more dimensionally stable than standard printing paper, with surface properties optimized for adhesive application and wall installation. CBP may consider the paper's weight, formation, and any manufacturer documentation indicating its intended use as a wallcovering substrate. General-purpose printing or writing paper of similar weight would be classified under other subheadings of heading 4802, so end-use documentation from the supplier is advisable.