From what I've read the post is actually welded in one or two small spots. Grind those spots and it should slide out.
That being said, if you are parting in out, most likely the post itself will be of little value so if you wanted to ship the post with the base I'd deal with it.
The wheel, base, pedestal gearing assembly (whatever you call that) compass, and engine controls I suspect will be of the most value.
Good luck with the sale and thanks much for the response.
-Chris