Read more about the temples before arriving: time at Abu Simbel will likely be limited, with little time to read about the stone carvings inside the temples. Beyond the temples themselves, the detailed description of sawing and moving the stone cubes is also an interesting story to read.
As with the pyramids at Giza, reading about them, before arriving, in no way diminishes the impact of seeing them firsthand. The reconstructed temples at Abu Simbel appear entirely real, not like a simulated building at some theme parks; however, do go inside the dome of the Great Temple to appreciate that it is a fake mountain.