The entire Sojourner rover was about the size of one of Curiosity's wheels. Beyond the size, they've redesigned the wheels with each generation of rover. Here's an image showing the 3 next to each other: http://www.flickr.com/photos/nasahqphoto/7706978152/

Also, I think that RipVan might be misremembering some details in that story, because it doesn't sound right at all. First, Sojourner didn't have any visual odometry capabilities, so wouldn't have had a reason for a specific pattern in the wheels. Also, I've seen tons of pictures of Sojourner, and the only pattern I've seen has been the zig-zag of the cleats on it. It's possible that any morse code pattern on it was always against the ground in all photos, but that seems unlikely.

Beyond that, I just don't buy the fact that JPL sees the rest of NASA as a bully. I only know one person that used to work at JPL, but he obviously has a great deal of respect for the entire NASA organization. And saying that NASA doesn't like the spotlight shining somewhere else is sort of ridiculous since JPL IS part of NASA. And, it's just not true that they're not allowed to logo anything. First, the website for every mission that's managed by JPL is hosted at JPL's website, and has their logo all over it. Yes, even Pathfinder/Sojourner had a website when it was launched (JPL still has a copy of the site up, if you want to be reminded how bad web design was in the mid-90s!). Also, the mission patches almost always have the JPL logo on them. Here's the one from Pathfinder: http://space.jpl.nasa.gov/art/pix/path640.jpg. And finally, at least for Pathfinder/Sojourner (the first Rover), JPL's logo was actually on the launch vehicle! http://upload.wikimedia.org/wikipedia/commons/9/9c/Mars_Pathfinder_launch.jpg