Proof 30c Black plate proof on stamp paper (228Pa), B. sheet margin single with immense full selvage, full o.g., never hinged, very fine, Scott retail $675.00 (half the pair price) photo

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Proof 30c Black plate proof on stamp paper (228Pa), B. sheet margin single with immense full selvage, full o.g., never hinged, very fine, Scott retail $675.00 (half the pair price) photo