I found this video...
The video says BS 008
I mic'd out my o-rings, which are in pretty bad shape, but the size looks correct. 0.070, 3/16 id, 5/16 od.
mcmaster has these
http://www.mcmaster.com/#o-rings/=i1vd39
I opt'd for the square ones, because I don't think the o-rings are...