Got a replacement FD off CL today, Tiagra road triple braze-on, FD-4503. And it has a nice solid curved washer to replace the flat one I lost on the side of the road.

Took a look and this one is helicoiled for the clamp bolt as well. As far as I can tell, from all the samples I have taken, 100% of all FD are helicoiled!