The Jeg's probably won't work, if you remove your handle you will see the inner shaft which is spring loaded, this pushes the "J" bar to allow gear selection, You will also note the slots cut into the outer shaft which align the handle and the smaller groove cut around circumference; this is where the "U" shaped handle retaining clip slides in to hold the handle on at the correct height,As referenced before, other GM handle's alignment tabs are 90* out of synch w/ the Buick's.
I tried to cut additional grooves in my shaft in order to use either Buick or other GM handles but it weakened the shaft too much. Other than the slot alignment , other 200r-4 floor shifter shafts should be the interchangeable.
Perhaps someone else can chime in to verify?