Tom - here is the link to the 2008 Class rules from the J/30 web site: http://www.j30.org/html/rules.html

Scroll down all the way to the bottom. That J/30 scaled logo is what has always been in the rules. It was there from day one when J/Boats first assembled the rules. What happened is that the original rules in booklet form had some of the images on adjacent pages, and this was one of them. Over time when the pagination was redone, this image got moved. Nothing really changes other than to restore what the figure was with the original rules.

Now - if you bought a J/30 one design sail from a sail maker, they probably already had the J/30 logo template and used it. I doubt that any sail makers took the time to come up with their own funky J/30 logo. So, you'll just need to verify that your logo looks like what is in the specs.