I've got a receiver end plate adapter for a sling that I'm not going to need. I've also got a HK style snap hook single-point sling (CQB Solutions with ERB) that I'm not going to need. I just don't like the single-point slings. I've installed & removed the adapter once and I've clipped the sling on the adapter once, but that's it. No scratches or anything. I can send pics if you're interested.
If you're interested in them I'll sell them together as a set for $50 shipped.
You can email me direct at email@example.com
ETA: Here's the sling (will check when I get home tonight to make sure): HST Sling
. The only diff is mine has the snap hook added.