So, although I find this pretty plausible, contemplating their unique armor-plating and the size/health/damage of his mom, not to forget the reward-gun, where does this come from? Maybe I've overseen some little sentence in one of the quest-texts, but I found no clue for this yet, despite the aforementioned. A source for this would be nice(or maybe just a little sentence like "he is revealed to be skagzillas grandson by [...]", for everyone to verify)
Hopes for the future
I hope that Dukino makes his return (either n a follow-up game or in a DLC) as a grownup.
I imagine him as Dukino, The Invincible...A Skag big enough to slurp down Terramorphous like a spaghetti.