Morgoth's Iron Crown~The One Ring?

[Legolas]

"innards" is slang for "inwards." It's very informal and in light of Tolkien's background, it would be truly odd had he used "innards" instead of "inwards."

I do not think the original post is saying that the Iron Crown was Morgoth's Ring as the One Ring was Sauron's - it's simply making an observation. The principle of weighing down their bearers is very similar. The bearers take on the heavy burden of these beautiful/powerful objects despite their weights because of a selfish, unhealthy obsession.