Recording the date at which a change was pushed to Savannah

[Glenn Morris <rgm@gnu.org>]

If I've understood correctly, "the date that a change was applied to the
Emacs repository on Savannah" is not something that is recorded.
Neither of the two dates that git does record correspond to that
(neither of those dates seems especially useful to me).

I've seen it suggested that enabling the reflog on the server (and
disabling expiry), plus a post-receive hook to add the information to a
note, will do it. E.g.:

http://mnaoumov.wordpress.com/2013/01/31/git-get-push-date/

Is it worth implementing that, or should I give up my quaint, naive
desire to know "when did X happen"?