What’s up with Buck’s magnum? Missed detail

As seen below, the front part of his iron sight has the same ‘tongs’ seen on the projection sight… But why is it floating? It’s clearly not attached. Is it a mysterious magnetic levitation sight similar to forerunner weapons or simply, kept in by mistake after remodelling the base magnum?

example of the “tongs”

its probably some of the details missing

A mistake they missed.

I mean, just look at Locke’s br in cutscenes.
It has no sights whatsoever.

Lazy Link #1

Lazy Link #2