As always - but particulary with
dynamic stamp markets - there is no substitute for knowledge of what you're doing.
It's an old story, but a dood one: the Jammu & Kashmir Circular types dating from 1866 have always been popular with collectors, and forgers. Corrupt Jammu & Kashmir state officials seem to have produced forgeries of the Circular types, which they 'introduced' into supplies of the genuine types. These forgeries were known as the Missing Die types, because they didn't agree in type with the legitimate issues, although they appeared on similar papers and inks. Here are specimens of the 4 Anna red Missing Die and genuine article:

In the so-called Missing Die forgeries, the central character (probably represeting a '4') aligns differently from the letters above.
And as for dynamic, the genuine stamp ten catalogue years ago (in 2008) was listed at £95, but this year (2017) is at £150. But only if you have the knowledge ...