Fat Albert & the Cosby Kids was Filmation's longest-running series, airing for 13 seasons (1972-1985), the final season as a weekday syndicated entry. One of the Junkyard Band's best known songs was "Begging Benny", which if my memory is correct came from the series' 1st season.
Like other pre-fab cartoon groups of the period, a Fat Albert soundtrack album does exist, but you'd be hard-pressed to find it. It's that rare. With the series resurfacing, airing Saturdays on RTV (check your local listings) beginning October 2, you can bet there'll be a clamor for the album to finally be released on CD.