What is a model, except a three-dimensional reduced-size image of the plane?
The model designation is provided by the military, not the company, as part of the contracting process. The F-111D that I worked on was built by General Dynamics, while the EF-111 Raven was rebuilt from older models of F-111 by McDonnel-Douglas, IIRC.
Doubt it, F-15 is a USG assigned designation, "Eagle" is a company specific "common name" (usually or often not used in life - "fighting Falcon" (gag) versus Hoover, "Thunderbolt II" versus Hog...).
Boeing could complain about "dreamliner" or 787, but it'd be really, really, dumb (who cares about modeling passenger haulers?).
I don't have a clue about what would be the reason for such a stupid brouhaha, but it could kill what is already a lagging industry/hobby/learning tool.
PS: Clearing out my folk's house; found three trunks full of '50 - '70s kits, motors, and assorted parts, I'm already started with a "new' control line fighter I'll probably build and never fly...the BEST therapy.
IMO the jet design and the name of the Jet are in the public domain the second they contract to sell the plane to the US Military. It is commissioned by the military and thus if there are any trademark rights, they belong to the taxpayers.