Probably, although Martin was definitely not the first fantasy author to put a villainous faction/entity in the inhospitable frozen north, nor was he the first to have a villain with a zombie army.

Although I think the Mountains of Muscles are more likely just a border feature slapped in between the Necrolord and the ambiguous barbarians of the northern steppes, which are again a common trope but probably directly drawn from the barbarian tribes of Icewind Dale (Wulfgar’s people in Forgotten Realms).

Or Warcraft.