I agree with Unicus & Addicted, too.

BTW:  You have to be careful when working on cast for early TV series.  For example: Gunsmoke.  In the early half-hour episodes, there were 4 main actors: James Arness, Dennis Weaver, Milburn Stone and Amanda Blake.  Current TV practice is to list the names of the principal cast in the opening credits and the supporting (and sometimes guest) cast in the end credits.  Gunsmoke didn't do it that way in the early years.  All the actors were listed only in the end credits.  And if Chester, Doc or Kitty weren't in a particular episode, Dennis, Milburn or Amanda weren't credited at all.

At some time later on, all the principals were credited up front whether or not their characters appeared in the episodes though most times they all did.  At least until Milburn Stone was recuperating from a heart attack(?) and Pat Hingle joined the cast as a substitute doctor while Doc Adams was in the East studying (or something like that).