How exactly is Godzilla undervalued? It's a $100 comic, because you think it should be?
There are always examples of comics that some people think are undervalued. I can remember reading similar statements about this comic or that in Overstreet market reports from 25-30 years ago and in this super silly market we're seeing right now, who is to say he's wrong? I mean, I don't think Godzilla 1 is undervalued but who really knows? In any event, it's all opinion.
And no, Herb Trimpe art is not a legitimate justification for a premium in any case.