As the OP stated, he is looking at a used pair of cables, so the figures you noted are a bit misleading.
I have used Supra cables for years and think they are neutral high value cables. I have no idea how the Swords compare. In the end, you really would never know unless you hear them in your system. Here's a thought. Offer the seller a nonrefundable rental fee of say $100 to audition the cables for a week that can be applied to the selling price if you buy them.