My guess is it is a low probability it is a ball bearing as it is a 930 direct fit turbo and they discouraged ball bearing systems on CIS cars back then.
For an oil restricter see here:
TurboKraft : Catalog Home : Garrett Turbocharger Oil Restrictor Fitting [930 107 125 TK] - $18.00
If someone is going to call Vission it would be good to have the size of the cold side intake just in front of the wheel and the hot side just at the exit of the wheel. With that one could probably identify the cold inducer and hot exducer.
Me, at that price I would just buy it. It will most likly be better than a K27-7200. IMO.