This is a set of 4 British Guiana Stamps, SG 01, the OFFICIAL OVERPRINT in RED on the 1 Cent Black, issued in 1875.

These are plated types A, B, D, & E, accounting for 4 of the 6 types.

These stamps are all used and in Fine to Very Fine Condition, and valued at L 110++ in the Stanley Gibbons Catalogue.