| Issuer | Date | Desc | State | ||
| - | no image | Gabon | 1/26/1988 | empty sheet (#21844) | incomplete |
| - | no image | Gabon | 2/17/1988 | sheet of 4 types | all added |
| - | no image | Gabon | 7/1/1988 | empty sheet (#21846) | incomplete |
| - | no image | Gabon | 9/17/1988 | empty sheet (#21847) | incomplete |