It's literally random with them, so I would just ride whatever winds blows, in this case. I'm simply pointing out they have an ironclad case IF they got grumpy.
As czar pointed out, given the title's age, they're
unlikely to get pissy.
However. Some of the engine is actually still in use; part of it was used in F.E.A.R., and part of
that was used in Shadow of MORRRRRRRDOORRRRRURURURURURUH, so if either party got grumpy, they would have legit cause.
Again, I'm not saying take it down, just cover your ass.
Published work statute is 25 years standard;
http://www.copyright.gov/title17/92chap1.html