I went to high school in the 80's (the late 80's!), and it wasn't much of an honor then. I think about 1/4 of my class got it. Looking at their website, it looks like you need a B grade point average and to be nominated by someone at your school. I bet the nominations is what leads to such a variation in who gets it at different schools.
We didn't buy the book, but I remember looking at a copy at the library and being unimpressed. I bet libraries still have copies, if you want to check out how many people get this. I think it barely outranks those poetry contests where win, get 'published' and can buy the book.
Rachel
p.s. I would /not/ mention it on a college application. It's just going to dilute your kid's real accomplishments and make it look like you're reaching for stuff to put on the page.