Yep!Thanks for the response!
Since there's no room for lateral movement in my bridge, I suppose that's just a vestigial part of the standard saddle part for bridges that actually -do- have room for adjustment. Makes sense to have a standard saddle carrier...
[Edit...] After having had another look - I think maybe you were telling me that's the lock for the actual 'V' of the saddle fulcrum pin, which could conceivably be moved side-to-side in the support block. All mine seem pretty happily in the middle so I'm leaving them alone - either way! Thanks again...

