Actually, we are. Mt. Gram happens to be in the game. It's that tall, prominent mountain immediately northwest of the Creep camp in the Moors. It's called "Gramsfoot" for a reason; it's a shortened way of saying, "The Foot of Mt. Gram." It's not - accessible - for gameplay, but visually speaking, it's there. It's true that it's unspecified in the lore as far as its location goes. But LOTRO already staked its claim / version of it.
Further, if you really climb around that troll arena in southeast Angmar and look in the direction of the Moors, you can see that same tall, prominent mountain jutting upward precisely where it is behind the Gramsfoot camp in the Moors.
Mystery solved. Now, will we only be able to see it from a distance and go nowhere near it due to its proximity to the Moors? That's the question.
Cheers!