Ohhh... IC...
The original ES1-M prototype also had a hole in it... But the people who he had try them out didn't like the opening hole. So he revised it, and only used disc openers on all his other folder designs (except for the proto of the I&I Tanto, it started out w/ a rectangular hole).
My only guess is that the CQC-9 was an older design... or that it was such a "purpose oriented" weapon that the other rules didn't apply.
PS. The "Emerson Straight" now also includes the CQC-10 w/ the oval hole...
PPS. Actually, *all* the new designs seem to have opening ovals, ie. Karambit, Hardwear line, etc.
Edited 'cause i can't spell.