Overly complicated vise stop

[Toolmaker51]

It's not a "Overly complicated vise stop", you worked around their design to accommodate a needed feature. It [the frame] might have been made one piece; no fun in that. Proof's in the pudding, that it remains in place. Rather critical function for a stop.
I notice at least one side of the body is drilled and tapped, opening a new opportunity for an extended stop.