The One and the Road Hawg do not have the same coverstock. The question was asked a while ago, and I couldn't find the post, but I think it was Ron Hickland who replied and said they're not the same coverstock. The Juiced coverstock only has an oil absorbtion rate around 6 grams, as opposed to the 10.7 grams of the One's coverstock. He also said even though Ebonite owns Hammer, Hammer and Ebonite develop and produce their own individual coverstocks. That means Hammer hasn't used any Ebonite coverstocks.
The coverstock is usually the biggest factor in the price of a ball. That's why Activator isn't on any BVP line balls for Brunswick. That's why the Paradigm is so expensive. If GB 10.7 is such a technologically advanced coverstock, it probably wouldn't appear on a ball at $40+ less than one it is already on. Coupled with that and the fact Hammer doesn't use Ebonite coverstocks, I'd say its as possible GB 10.7 being on the Doom as Activator or EOX.
Perhaps the Hammer Rep was saying the One and Doom have the same coverstock based solely on reaction?