If your question is purely about whether or not viewport clipping is supported with each of these rendering methods, the answer is Yes. Viewport clipping is part of the rendering pipeline and it makes no difference how the triangles got to that stage of the pipeline.
But we can’t tell you in good conscience to use immediate mode nor display lists.
Immediate mode has been deprecated for ages and is terribly horribly slow. Display lists have been deprecated for a shorter period of time but are deprecated and their use is entirely discouraged not only by people who know what they are doing but also by Khronos. Considering how easy the switch is to VBO’s from display lists, there really is no reason not to do it, so I really can’t understand why you can’t just use VBO’s and be done with it.
In future versions of OpenGL you won’t even have the choice not to use VBO’s—it will be required that you do.
thanks! I'll definitely go with VBOs