Late reply but yesterday I took my bar end off to try and fit my Kaoko throttle lock which I bought from Zippy ages ago...
My handlebars didn't have that welded insert in it - see pics inc stock bar end.
I think I've installed it correct although I may have used an extra spacer than needed
will have to give it a try when the weather improves and see if I prefer it to my cramp buster which I've used for years as don't think they both fit together...
I also should have taken a picture of it installed with the OEM handguards which I put back on the bike yesterday too. Will take one tomorrow and post