Believing in attributions is always a tricky business. Once you have a reputation as a pundit, people will credit all kinds of witty remarks to you.

I've heard
-- "If I'd'a known I was going to live this long, I'd'a taken better care of myself!"
for example, ascribed to Eubie Blake, and to Winston Churchill, and to Mark Twain. (But not to George Burns or Bob Hope. Yet. There seems to be a fairly limited overlap.)