Are you specifically asking for a 2.1 context?
This is important since otherwise OSX might give you the highest context it can give you (ie, OpenGL 3 context), and since OSX lacks an 'arb_compatibility' profile, your code using GL2 features might mess things up.
EDIT: You can ask specifically for a 2.1 context with LWJGL like this:
// Standard pixel format. alpha, depth, stencil.
PixelFormat pixelFormat = new PixelFormat( 8, 24, 8 );
// Context attributes, 2.1, major version, minor version.
ContextAttribs contextAttributes = new ContextAttribs( 2, 1 );
// Then you create your display like:
Display.create( pixelFormat, contextAttributes );
Thnx i didnt know that. Il give it a try.