understanding locks

[KDubs]

 So I have researched a bit and I am trying to understand what is meant by a round face vs a flat face vs a ketland etc lock.
 what is the face on a lock . what makes it flat,square or round.
 I see plenty of pics of these locks but I can't tell what's what !
  how do I tell these locks apart or know what I'm looking at.
 Hope this makes sense.
 thanks kevin
 

[BEAVERMAN]

Flat face is like a TC or Lyman, round face is like your Kibler or what you see on a Bess, Ketland I still haven't figured out

[KDubs]

Ok but what is referred to as the face.
 Is it the lock plate, the jaws of the cock.
 I think that's where my confusion lay.
 
Thanks beav for the info so far.
Kevin

[rollingb]

Lock plate. 

[KDubs]

10 4.
 After looking at more locks that was what I figured.
 Kevin

[Hank in WV]

The outside of the plate.