I think the one you're thinking about is Kaboom but the bonus round on that is different from the Planet Moolah and the newer games. The one I found played exactly like the Planet Moolah with more turns depending on how many levels you made it through (i.e. number of wins in one play).

At Harrah's in AC they have ONE Planet Moolah in one of the Monopoly Big Event groups but they have over half of the pay lines disabled so the odds are extremely bad. You almost never win anything on it.