Those are the ones.. but I used the oem O-rings and they fit just fine. My 630cc's and the 840cc's look identical.

 

hmm, yeah I used the OEM o-rings too, I guess it was just the location of that one or something, but it fit a lot better after I made it look more like the OEM ones, when I tried putting them into the rail to see if itd seal before I modified them they wouldnt stay but after wards they clicked in like the OEM ones do