Sorry Bill - Your GH has the usual Parker D3 (3 Iron Oxford) and I believe the rib is a large scroll likely 2 Iron Oxford (notice the scrolls are oblong rather than round) but oriented 90 degrees to the barrel pattern, but could certainly be wrong. The Hufnagel barrel with a 'Star' rib at the start of the thread probably are the same pattern, but as Craig said the rib was ground deeper.
More information here
http://www.picturetrail.com/sfx/album/view/19025099 Could you please post an ultra closeup of the pattern of the side of the rib?
