Well, I was so proud of the kid and his eagle eyes that I tweeted Hy-Vee and told them about it. I sent them a link to my blog. They tweeted back and asked for my contact information.
A few days ago the store manager called and said he wanted to give Henry a dozen free donuts (with my blessing, of course) for spotting the miscue on the sign.
Doesn't he look like a proud proofreader? Thank you, Hy-Vee, for making Henry's day!