I released my Step 2 scores to all programs the afternoon after I got the results back. On ERAS, I saw that all the programs where my application was still pending had downloaded the updated reports within the next 2 days. Judging by the longshot interview invites I've received since then, I have a feeling it MAY have impacted their decision.
I did not contact any of those programs by email with an update about the score. However, if your Step 2 CK is significantly higher than your Step 1, that might be a good idea this late in the game. At least it can't hurt.