I doubt it,they had a laugh over it after they said so and the comment of Roger Allers being the father really doesn't make me want to believe that they were serious. Other than that, a lot of things from the TLK universe, if you look at it just from that point of view, wouldn't make sense if they were related.
But yeah, it's your choice to believe what you want and mine to believe what I want, I think it's best to leave it at that.