Unfortunately, the disappointing answer is that you may not be able to find the exact release dates. You'd be amazed how many brand spankin' new CDs I buy even to this day which don't have a release date anywhere on them.

Discogs is a good resource. They list 12 versions of For the Family and 13 versions of From Fresh Water. Based on your descriptions, I'd assume the correct releases on there are [r2362419] and [r2501309], both of which are CDs with no release date.

Anecdotally, though it's possible, I'd be surprised if the CDs were the same age as the album's original release years. CDs were commercially released in 1982, and for most of the first decade were only available from the largest, most commercially-successful artists and performers.