Joined: Jan 2010
Posts: 9,835
Likes: 1,816
From: Northern California
Bikes: Cheltenham-Pedersen racer, Boulder F/S Paris-Roubaix, Varsity racer, '52 Christophe, '62 Continental, '92 Merckx, '75 Limongi, '76 Presto, '72 Gitane SC, '71 Schwinn SS, etc.
Could these simply be like standard road pad/holders, using a mounting bolt instead of a nut?
Nothing new about that, many contemporary brakes secure their holders that way.
So likely there is a bolt and the usual stack of spherical washers needed to mount them to a standard road caliper.
It doesn't look like these are adaptable for canti brake use, but maybe they offer a version for that?