The main color is dark grey. (It comes out greyish blue from my scanner, so I can't post scans. There is no trace of blue on the actual box.) The lighter stripes are just normal grey. Can't wait to see the boxes.
Your current version has a mistake. The ratings box uses the wrong font, (causing some letters to be a little taller then others) and has a drop shadow beneath the text. (which the original did not have)
Comparison:
This vector file is a okay replacement (although you'll need to cut off the bottom descriptive text and tweak the text placement to make it look like the original)
http://www.seeklogo.com/motion-picture-association-pg-rating-logo-95036.html
Scratch that, the ones in this pdf (on page 18) are official and look nicer.
web.archive.org/web/20081111133643/http://www.filmratings.com/2006Handbook.pdf (copy and paste the whole url, the forum dosen't want to make a clickable link)