Were you a costumed CM? When were you there? I'm glad it had some effect in your case.
Over the 20 plus years as a CM, and having held many high visibility positions with lots of one on one guest interaction in all of them, including the current position, I was never told that I got any of the positions due to the dozens and dozens of acknowledgments on my record card. I would have gotten them regardless based on other factors. That's not to say that it never happens.
I think that's a good thing because there are thousands of excellent and qualified behind the scenes CMs who aren't able to receive guest letters. If they're being considered for a position along with someone like me, who has had the opportunity to get countless guest letters, I don't think it's fair that I have an advantage. I wouldn't like it if things were reversed.