I need help in identifying these three over-printed Azores Islands MNH Stamps. Here is what I know about these stamps; which is very little. The design is listed under "Common Design Types": as CD22 (Embarking at Rostetills, CD26 (Flagship San Gabriel), and CD27 (Vasco de Gama). I've checked Scott's Catalog in Azores, Portuguese Africa, Portugal, and Portuguese India without success. My guess is they may be over-printed stamps that were never issued? Any info. will be most appreciated.