I thought that was weird, too...on the flipside, though, it's odd that this one's not in the Gerber guide, which begs the question...how rare is it?
One the one hand, one might argue that Gerber simply wasn't interested in a lot of giveaways and didn't bother to make a comprehensive account of them in the photojournals. On the other hand, it's hard to imagine that Gerber would have passed on listing anything with the title "Comic Cavalcade" in it had he be able to scrounge up a copy, given the significance of the series to GA DC history. Plus, he's got one of the other three CC giveaways listed, the more famous one with the Nazi imagery, so the absence of this giveaway in the gerber books is curious.
Thanks!