Sorry everyone, was away from my computer until now… Yes being the owner of the original photo, I can confirm that it has a radius on the inside (as Neil has blown up). So mine look like the version Michael Briggs posted but his have a nicer finish on the faces.
Funny how sometimes you're talking about the same thing from a different perspective! Sorry it's blown out of proportion.
Yes Hopper just the chamfer, so I'm guess whatever tool they use to clean up the edge created that.
For me my question still stands on why it is there to begin with (i.e. the undercut with a smooth radius) particularly on the vee holders, I've contact Bison to find out. I have some genuine Dickson's coming and from what I can see from the photos they don't have this 'feature' at all.