I was intrigued that the early script draft uses frozen fossils found in Siberia as a plot point. That would seem a nod to the Fleischer Superman cartoon "The Arctic Giant" from 1942 wherein a "Tyrannosaurus" is found frozen in Siberia and brought back to Metropolis where it is accidentally thawed so that it then rampages through the city until subdued by Superman. That monster is a proto-kaiju, not a tyrannosaur, green-skinned with dorsal plates, and this animated short surely influenced movies from "The Beast from 20K Fathoms" and the original "Godzilla" through to "Pacific Rim" (first kaiju assault on San Francisco).
At a little over 8 minutes, it is worth viewing:
http://www.youtube.com/watch?v=J5M1A_OQaaMI would be fascinated with how the frozen "Jira" appears if made clear in the script draft, and would expect that one might see a creature with possibly more regular dorsal plates, like the "maple leaf" back plates employed in the Heisei era suit designs. Since the script's living Godzilla survives several exposures to nuclear detonations, he should look different—ravaged, with more jagged spines, and show some signs of having been scarred and changed by the blasts. The modern incarnations of the Muto insects may also then be changed from their ancestors through radiation exposure if scientists hatch the preserved egg in the Japanese nuclear power plant. I am curious as to whether radiation is meant to be natural to the life cycles of the fossilized creatures, or an addition to their lives wrought by mankind's interference, which then would change the balance of nature thus putting the blame square on the shoulders of our species?