I'm guessing it was a marketing decision. Acclaim's Turok comic was due to hit the stands the month after Dinosaur Hunter's release, and it's possible that somebody at Acclaim went "hey, we have this comic with this Fireseed guy, let's change the box art so that people will conflate the two." Pure speculation on my part, of course, but as I said, entirely possible. There's not much different between the two anyway.