I posted that shot on Vintage about 2 or 3 year ago,The pic is taken from UK Action bike ,not sure what issue. Yeah its Rich Sigur,the frame has some weird features like the dropouts and gusset in the chainstays.
If you read through magazines it mentions that a frame was been developed for Rich,because of his height and this is when Dominguez was riding the GEN1 and rich was riding a Supergoose(Haro Sponsered) I reckon its possible that the Sport frame was originally built for Sigur in the begining but as Dominguez became Haro's big name the Sport was made a signiture frame for Mike .
Only a guess from info i've found hunting for info over the years ,and its no good asking BOB HARO,cause he can't remember nowt from BITD about these frames,we know more than him.....Who knows.