Always check the revision history at the end of the PDF. A genuine datasheet will list errata and update dates. Revision 1.0 dated 2015 is likely correct; revision 0.2 from 2014 might be a pre-release draft.
The HX8872C allows 10-bit gamma correction. The datasheet provides default values for 2.2 gamma, but you can adjust registers 0xE0 (positive gamma) and 0xE1 (negative gamma) to fine-tune contrast. hx8872c datasheet