s 12 Duplicate and counterparts
The duplicate or counterpart of an instrument chargeable with duty (except the counterpart of an instrument chargeable as a lease, such counterpart not being executed by or on behalf of any lessor or grantor) shall not be deemed duly stamped unless it is stamped as an original instrument, or unless it appears by a certificate indorsed thereon by the Collector that the full and proper duty has been paid upon the original instrument of which it is the duplicate or counterpart. Valuation for Duty