Yes, if I recall correctly Nebraska state law forbids the sale of any tractor that has not been evaluated by the University of Nebraska to ascertain its power and capabilities. I think the problem was that so many tractors were being sold under fraudulent claims that the law was drawn up; it has never been repealed and even now you can occasionally find a tractor with an asterisk under it, like this:
* Not available in Nebraska
Because it hasn't been through the testing.
UN keeps their current test results available:
Nebraska Tractor Test Reports | Nebraska Tractor Test Laboratory | University of Nebraska-Lincoln
This is fun but I don't want to distract from the thrust of the forum. But, Xpedro, if you're interested there are lots of tractor enthusiast forums you might be interested in. However out of respect to this site I'm not going to name any; just Google the search terms "tractor forum" and choose for yourself. I'm on a couple.