If it says 1.6.318.0 , you are ready. If it says anything higher (e.g., 1.6.640, 1.6.1130), you cannot use SKSE for 1.6.318 without downgrading.
While a jump from 317 to 318 sounds minor, in the world of executable binaries, it is a breaking change. The SKSE team works tirelessly to update their dll files to match the memory addresses of the game’s executable. When the executable changes—even slightly—SKSE stops working. Skse For Skyrim 1.6.318
Some older DLL-based mods were updated for 1.6.318 but haven't been touched since. If it says 1