Technically all monitors are overclockable through a setting in either the Catalyst Control Center or the Nvidia control panel, however, the effectiveness of this overclock can vary. It may result in heavier backlight bleed than previously experienced, can result in your panel flickering, artifacting and in the worst case, a dead monitor.
I wouldn't recommend it in your case, as that panel is not designed for a high refresh rate, and therefore will not have much headroom in terms of overclocking, if any at all.
If it does get a higher refresh rate, it will likely suffer from lesser color accuracy or clarity.