Would it be possible for DTG to use mods on something like train som community and use them in a loco like the sd70ace or sd40 since they have the correct sounds I don't see why not since the us horn sounds usually are provided by their contacts and not themselves
It depends on a lot of factors. Copyright, how the sound was sourced (what equipment, what angles, distance, etc) and much more. Sounds are also tied to physics so if the physics is wrong, sound is wrong which turns it into a much bigger project. It's not just a simple case of copy and paste