Along with Jeff, I would advise against it, just to be on the safe side. It only takes one grumpy customs official who got up on the wrong side of the bed to make your experience misreable, even if it turns out well in the end. Why risk it?

I, too, would gladly ship a lonaer to you, either a rabbit fur sporran or a black leather with silver (i.e., "shiny", not sterling) cantle. You could wear it, have fun at the wedding, and send it back when it's all said and done. And your seal skin would be safe at home. Our overly zealous PC crowd have taken a lot of the fun out of life, and this is only one more.