6¢ Washington Head
Flat Plate
Perf 12
Watermark Check - You will need to check the watermark on this stamp, however all the perf 12 stamps were printed by the flat plate method and there is no need to check printing method unless the stamp is suspect.
| Watermark | Number |
| double-line | 336 |
| double-line (blue paper) | 362 |
| single-line | 379 |
