Bidspirit auction | United States - Modern Errors

United States - Modern Errors and Varieties - 1983, American Inventors, (20c), bottom left corner sheet margin block of six, including se-tenant block of four and two extra values, all with black engraved color omitted, full OG, NH, VF, C.v. $275 for block of four, Scott #2058b, 2056, 2058 var