Yes they were. I vaguely remember seeing them on display when I was a kid at the wildlife park where they shot the show. It was shut down about ten years ago now because the animals were starving.
One thing they don't show in this is Skippy talking to one of the kids, who could understand him. Since kangaroos don't really make any noise normally, they would dub over this kind of clicking noise which sounded like morse code, then the kid would say "What's that Skip? Jewel smugglers at Donovan's Pass?" and the day would be saved.