The .txt file says:
* Copyright / Permissions *
Permissions have been obtained from original authors for any of
their resources modified or included in this file.
I have no idea if that is even referring to letting other people use its resources, but I don't see any mentions of "DONT USE THIS OR WE'LL SHOOT YOU IN THE FOOT", so yeah.
But since I am a colossal bastard, I just thought I'd mention that it doesn't take a lot of effort to go to the idgames database, look up Legacy of Suffering and find the author's email: firstname.lastname@example.org
Now you know how to contact people on the internet.