We never get to see Ned's armor and I doubt that Sandor has the only helmet in Westeros that looks like a dog (or in this case a wolf). There are numerous mentions in the books to other animal shaped helmets (bulls and whatnot) so I figured that the head of a major house might own such a helmet.
The coat of arms is actually a wolf as well, which I found in a book of heraldry. What's confusing is that numerous creatures look very similar in Medieval heraldry. But I assure you, this is Ned - just my take on his design.
It's interesting, because I wanted to make a helmet that was iconic, but still possible to make. I don't know if you've seen the show but their take on the Hound's helmet is a little fantastic for my liking. Anyway, in this series I've been doing, the other houses have armor more akin to 15th century plate, whereas the Starks have an older almost antique set of transitional plate. It may look flashier than you imagined, but the bascinet is still out of date and since there's nothing describing Ned's armor in the books and there's a slew of other animal inspired helmets out there, I figured 'why not' Glad you like the armor!