Slant Six Distributor O-Ring(s)

How many o rings should the slant distributor have? 64 Valiant with a 170. Removed my distributor for some work and it has two. One between the adjusting plate and block and another on the distributor shaft. Seems to me if it has the one on the shaft, that would seal any oil from the engine. Does it call for two or is this somebody's shade treeness? I tried looking in the service manual and couldn't find anything. If I have to have two where can I get them? Thank you drive through.