Sorry guys, I was a bit slow tonight.
As the others say, its nothing more than the peg mounts. Pitch-without, Ditch-with. The first dichforks just had a hole drilled in the leg, much like early hoffman forks. Then they moved to the ones with the big mount at the bottom of the leg so it looks like a small peg is welded to the fork leg. I have a feeling that 'Woody Allan Bars' will be posting a great pic of his to this thread any time soon (Ive got the pic but its his so I'll let him do it).
Happy to help when I can