This is an odd topic, but interesting nonetheless.
Current deadlift is just under 1000Lb. I'd wager the gorilla hand gripping strength is 4-6 x greater than a human being.
How much you think a 450Lb ferocious gorilla could deadlift? I'd wager over 2000LB the first attempt.
That sounds like a reasonable figure.
If he could go thru the motions of the benchpress, I have no doubt
he could bench press over 500Lb the first attempt.
If we could train a gorilla for the bench press, I have no doubt he could get over 3x that of a human being.
I think we should probably consider some anatomical differnces. A gorilla doesn't have the same frame as a human and might find it akward to find the dexterity to achieve this. I don't doubt the animals physical strength to achieve this, however.