The version of opengl32.dll depends on your OS and has nothing to do with what version of OpenGL your graphics driver supports.
By the way, if the library opengl32.dll doesn't exist (dlls don't exist on those OS) on Linux and OSX, do you need another type of library?
OpenGL isn't a software library, it's just an API. The architecture and implementation is different on various platforms.
In the case of Linux, libopengl.so is analogous to opengl32.dll.