I'm staying reserved on this one. The evidence points that Ash is getting one, but it could be an unintentional cruel joke.
If it is going to happen, I really like the idea of Cynthia giving Ash an egg and it hatches. Do I want it to be shiny or not? Gible/Gabite and Especially Garchomp don't have much of a difference between shiny and non shiny, it's not as drastic like Croagunk/Toxicroak. And since Ursula's Gabite is already a dark blue color, I don't know if there would be a distinction. They could go for an anime only coloring but who knows. Gible is the only one you can tell is shiny or not.
I don't know if I like Ash getting Kazunari's Gible though. As much as I dislike Kazunari catching it, looking back it does fit more with Kazunari than Ash. Of course that's because Gible and Totodile seem like a good pair.
I do think if this information is true than this episode set up Ash's capture up well. Miss out a chance to capture Gible because someone caught it, and then capture one later. This I believe would be the first time it's happened with Ash. Flannery owned the Torkoal so he couldn't capture it. And other times I don't think he tried to capture it when he saw it first but in a future episode caught it.
Edit: Besides it's not like it would matter anyway since Kazunari is leaving, it's much likelier we won't see him again. Maybe one or two more times, but not enough for there to be any problems with Ash owning one as well.