Our friends at Tricycle will push through a zero-based karma system (no self-voting possible) sometime this evening. At present this will only cover future posts/comments - they may go back and revise history some time in the indefinite future (or not), but apparently that would be overly complicated for now. We'll see how this works.
Do we still get an immediate karma point for posting a comment?
(I'll have answered my own question by posting this, and will edit with the answer momentarily.)
Answer: no.