Picked up a used 555 Mini-Grip 440C with the oval hole this past weekend. It's a great knife, it pocket carries very well and is a lot of fun to open and close.
This MG has been stropped so it probably has a convex edge, it was pretty sharp and not abused at all. After some time on the old school Crock Sticks it now cuts paper pretty well even if it isn't razor sharp.
Now to get one with the round hole for comparison......