There is no saying that even though you can download a new file for your Atlas engine, will you be able to for free? Who will hold the library? I assume the new DCS tech group would and will they still offer them for free? Some unknowns yet.
Marty I scraped the MTH Website a while back and grabbed EVERYTHING. Manuals, schematics, and every single sound file. People talk about 100's of MTH sound files, it's more like 10's of thousands. The MTH sound Library is currently free and public, If you are worried, go get em now I say.
However, I don't see why they would stop offering them for free, think of the backlash this new company would get from the start. Plus it's not like MTH can stop the flow of information of theses files being shared on the internet from other sources.