I am actually leaning towards the border being iron for us, but you can barely see it due the forum background being so white.
It is somewhat that color, but it's not shiny like the perimeter for a Knight.
Possible Bug: I notice that some armatars have a "taper" on their corners.
Screenshots to illustrate both the response and the bug:
The first screenshot has 4 different armatars.
pangtongshu has a tapered armatar in the above screenshot. The other 3 armatars illustrate the perimeter for a Knight, a Moderator, and a normal user.
Here's the second screenshot, which only has 1 armatar:
The armatar in the second screenshot is not as severely tapered as the first (belonging to pang), but it does show that the taper doesn't seem to care about gender, and that the taper bug has multiple levels.
Your's and Pang's Armatars are very different and as boppins said it will go away after a while so I don't think it does
That's true, but I just happened to notice that if you look close enough it looks like the armatar is too small for the border. I just wanted to say this, even though I know it will be fixed soon.