Take that article with a grain of salt. That particular hatchery does not sell HBG, instead preferring to push CNBG. CNBG are certainly a fantastic fish, but many, many anglers have caught huge HBG over the years and gotten great enjoyment from them; they're also recommended by multiple state game and fish agencies (not that that makes them a perfect fish, just that they're not the plague the Suttle people make them out to be). It is true that HBG degenerate genetically after the first generation, and become closer to GSF in growth potential and rates than HBG; but they're not the same as GSF.
Your fish is almost certainly a HBG, and as such has a good likelihood of getting very large, especially if you're feeding which it sounds like you are. Two-pounders are common; I've read reports of three-pounders though I haven't seen any that size. And, with 100 LMB and 30 hybrid striped bass in a 1.25 acre pond, you have about a zero chance of the HBG offspring overpopulating unless you fish both predator species down severely.
