I got this from a dealer at a Gun Show that used to be held in Greenwich CT years ago, it was a high end show, mostly SxS dealers and custom rifles upstairs and parts downstairs. The seller was strictly a Winchester guy, all sorts of hard to find stuff like this.
Sold as a package, 1-1/4" Super Grade swivels with 1-1/4" sling. Leather is supple, no cracking, brass hooks are heavy gauge.
$475 plus shipping....
Link to photos..