I dug my Scheu out of the closet (it's been there since I moved) and looked closely at the bearing. I bought mine about 10 years ago and it looks exactly like the one in the pictures that you linked. I have the smaller o-ring which helps to seal the inner bearing to the oil pan and prevent oil from dripping out. You definitely need this. You should be able to get this from a good quality hardware store or if you don't want to hunt around then call your local distributor and they should be able to send you one. If you're in the U.S., that would be Tom Hudson at http://www.hudsonaudioimports.com/
Or just contact Scheu directly. You can find the information at their website http://www.scheu-analogue.com/en/index.htm
I also have the larger o-ring and that is meant to go on the outer bearing as you've shown. The people who steered me towards the Scheu recommended not to use this o-ring and instead just replace it with an appropriate steel washer that is 1.5mm thick and with inner / outer diameter of 20 / 23mm. That's what I did and I've been very happy with the sound.
---Gary
Or just contact Scheu directly. You can find the information at their website http://www.scheu-analogue.com/en/index.htm
I also have the larger o-ring and that is meant to go on the outer bearing as you've shown. The people who steered me towards the Scheu recommended not to use this o-ring and instead just replace it with an appropriate steel washer that is 1.5mm thick and with inner / outer diameter of 20 / 23mm. That's what I did and I've been very happy with the sound.
---Gary