The guitar industry in general did not pursue copyright issues for most of the modern (electric) guitar era. Based on what I've read over the years, the various court cases and judgments don't really add up to a workable response to the basic "how similar is too similar?" question. So it's easy to see how litigation springs up, because it's only in court that the boundary gets determined. Personally, I do not respect copyists like Dean, period. If you do not have a distinctive product to market, using someone else's design, legally or otherwise, is just kind of dishonorable and certainly uncreative. If someone can look at your thing and say, "That's a Joe Schmoe guitar, and that's what I want" because Joe did X, Y, Z" instead of "Joe Schmoe's version of the Gibson is cheaper" then good for you. I think the Deans are copies with a few tweaks, mostly superficial, but the courts and others can decide. Just my opinion.