Yes — cocoa paste and cocoa liquor (also called cocoa mass) are trade synonyms for the same product: finely ground cocoa beans in liquid or solid form. Both terms refer to the same article under heading 1803, so the commercial name used on invoices does not change the classification.

The degree of fat removal is the criterion. Paste that retains its natural cocoa butter content is classified under 180310 (not defatted), while paste from which some or all cocoa butter has been extracted falls under 180320 (wholly or partly defatted). Laboratory analysis of fat content may be needed to support the declared subheading.