I go by the assumption that a high-value (rare) stamp from classic Germany has
been forged, unless it has an expertizing mark (preferably from the BPP, the
German expertizing society). Even signatures are forged these days. This database
of signature marks helps
http://www.stampsx.com/briefmarken/...gnaturen.htmThe catalog value (CV) of this stamp is EUR 100 with no gum, so a signature
is required. Specially since there are forgeries from #7 or #12 (cutting the
perfs). This one has good margins, so that is not the case.
Of course a certificate (Fotoattest) of the expert is the best, and for me is
a requirement to buy a $1000+ catalog value stamp.