Ritchey I beams, they be. the theory behind them was they would be more effective, being stiffer with the double sides to the main beam, but in practise they tended to squeal a bit as did other similar designs. Worked very well though.
The reason why Shimano and Avid brakes work so well, is that the arms are designed to rotate inwards, upon pad contact with the rim under pressure, this "enforced" toe in creates "bite" and prevents squeal.
The proof of the pudding was that the Ritchey team didn't use them for long and from -95 specced M95# XTR.
If in good Nick worth £50 ish a full set.