Should there be an o ring / gasket on the actual keg part of the corny post?

[Beardown]

I am getting a leak rt there and thought I remembered there being an o ring on the keg part of the post? If so/ size? So when screwed in a o ring sealed the post to keg,

 

[Jawbox0]

There's an O-ring on the end of the dip tubes.

 

[Beardown]

Yea it seems to be good though, I guess I change it out and see,, the leak is fixed for now cause I cranked the crap out of it,,,

 

[pvpeacock]

0-ring on dip tube + o-ring on poppet + o-ring on post

http://www.wikihow.com/Assemble-a-Cornelius-Keg