Watermark Check – There is no need to check for watermark or plate type other than for authentication purposes, since both of these stamps must be flat plate, type I and single-line watermarked.
|Coil Type||Printing Method||Watermark||US Number|
|Vertical Coil||Flat Plate||Single-line||411|
|Horizontal Coil||Flat Plate||Single-line||413|
The 2¢ perf 8½ coils, US 411 and 413, are sometimes faked by adding perforations to the common imperforate stamp, US 409, since the cost of certification outweighs the value of the stamp. Examine the perforations carefully to insure they are genuine. Examine guidelines with the foil method to make certain they were not drawn in.