It is unlikely that unused copies of this
stamp would be faked by trimming a perf 10 stamp, since the coil is less
expensive than the fully perforated stamp in the unused state. However, the used
coil stamp may be faked by trimming the perf 10 stamp, since the coil is
valued about 10 times more expensive. Fortunately, this is an easy
stamp to check, if it is rotary it is genuine, if it is flat plate it is
fake. Therefore it is advised that the 10¢ perf 10 coil be checked for printing
method.
The most common fakes of this stamp are the line pairs, since
creating one from a normal coil pair simply involves drawing in a
line. The line will not be engraved, however, and will not create an
impression on thin foil (see the "thin
foil" method.)