Is it a skill? I was under the impression it was just a sort of past-time, similar to woodcutting.
Seeing as there's a skill for it, I'd say yes, it is a skill, my guess is that "smithing" will cover both making weapons and armor and the funtion of armorer in past games.
Myself, I think the picture linked tomore or less answers the question, and I've actually used it as evidence that smithing is indeed a skill before, albeit the unedited version that shows destruction rather than conception.
And I'm guessing the skill that ends in "aft" is "speechcraft".