The large issues of the reign of Shah Jahan Begum, that is between SG 1 to SG 78, were embossed with her octagonal seal. The issues made during the reign
of Sultan Jahan Begum, that is SG 79 to 98 and all the reprints and imitations
received her circular embossed seal.
So, for example, this stamp
must immediately be classed as an imitation. Although it's in the style of the issues of Shah Jahan Begum, with the blank centre for the embossing, it has her daughter's seal. Hence it can't have been issued during Shah Jahan Begum's reign.
The only crossover stamp was the 8 Anna of Shah Jahan Begum overprinted with the Persian 'S' for Sultan Jahan Begum
and as it had the seal printed as part of the design, and was too small to accommodate it, it didn't receive the embossing.