Yeah, I have read quite a few posts and some say it is correct and
others say it was like an add-on. I have read posts that say you can tweak the quarter slightly if you
don't have it. Sounds to me like it was a TSB change. The plate looks like that horseshoe bracket
would fit through it and give more surface area for the antenna to flex against, making a larger
area a bit more rigid. I don't know if flexing was a problem or not.