Gretsch jumped on Fender almost immediately. The Broadcaster was only on the market from 1950-51 before Fender had to get rid of the name.
As for the Hummingbird issue in the current Gibson lawsuit, I don't know how long Luna has had the Hummingbird line, but Luna has only been in existence since 2005.
The focus on the 40 year run where Dean has made guitars that look like Gibson guitars deals with different models. Those are the Dean V and Z, which Dean introduced in 1977. To me, this will be the trickier one for Gibson to win, as Gibson didn't trademark the V and Explorer shapes until 1997, even though they were introduced in 1958.
Then again, it all depends on how a jury (which very possibly won't have a single guitarist on it) views these things. The actual V and Z body shapes are nearly perfect replications of the Flying V and Explorer shapes, which are originally Gibson designs. This cannot be denied. I suspect Gibson will try to hammer that point. On the other hand, I suspect Armadillo will draw attention to the finer nuances of how long Gibson has left these things unchallenged, tacit consent, and so on.
It will be interesting to watch.