No, past versions of the plugin are not publicly archived--that appears to be the convention for calibre plugins. I've attached 1.7.13 to this post for you to try. But be warned that I'll delete it again in a few days to avoid cluttering the forum.
FFDL doesn't populate calibre's Rating column. Calibre's Rating column is a 1-5 star rating. FFDL's Rating is a text string that varies from site to site. MA, Mature, General, YA13, Not Rated, etc, etc, etc.
If you want FFDL's rating in a column, you'll have to use a custom column for it.
Rating from http://archiveofourown.org
is working fine for me. Are you sure you didn't do something in your settings trying to make it appear in the Rating column?
UPDATE Mar 24, 2013 -- As promised, I've removed the attached zip. There's nothing wrong with 1.7.14.