I do not get it, I only see one tusk in these photos. Because the bottom photo is flipped.
Rondan, it looks like both horns are visible in that top behind-the-scnens pic to me - with the tip of the ‘broken-ended’ one just visible on the left of that pic.
As far as I’m aware, the bottom pic (which is ‘flipped’ compared to the way it looks in the top pic) was taken when the wampa puppet was on public display somewhere, sometime after the movie was completed. And somewhere along the line, the hair on the puppet ended up re-arranged somewhat, and ended up covering one of the horns completely in this pic.
@ Ronster - Gotta say that I was never partial to the look of McQuarrie’s wampa design, nor the curvature of it’s horns in that particular concept. I much prefer the horns to be angled more in the style of this myself -