EXTREMELY FINE. THIS IS THE ONLY RECORDED COVER WITH CLASSIC COLOMBIAN STAMPS USED ON THE FIRST DAY OF ISSUE. MORE IMPORTANTLY, IT IS THE ONLY FIRST DAY COVER OF ANY AMERICAN FIRST ISSUE, INCLUDING THE UNITED STATES AND CANADA.
This cover is illustrated in Dieter Bortfeldt's Colombia Philatelic Handbook and Catalogue 1859-1860 (page 4), where it is described as "Cover dated 1 September 1859 - The ONLY known cover from the FIRST DAY." The handstamped postmarks on early Colombia covers usually did not have a date (except for the Medellin receiving mark).