OpenGL 3.0 Deprecation -- Ancient Functions

I just want to see if my conceptualization of how 3.0 deprecation works is correct:

If you have a forward compatible context (one that actually takes out the deprecated items) then glBegin, glEnd, glVertex*, and other such ancient functions will still be loadable via glXGetProcAddress and the like, but they’ll just generate GL errors if called.

Do I have that right?

The wiki has a decent article explaining how this stuff works.

As to what glXGetProcAddress specifically will return for functions that are not available, that is not known or specified by the specification. But if it does return something, you should not call them.