James Arness had a real limp.Chester, (Dennis Weaver) in the Gunsmoke
movies, before Festus (Ken Curtis) showd up, Chester had a fake
limp.They wanted Chester to have some kind of a schtick, so Dennis
Weaver 'invented' his limp.Sometimes he would fall down when he was
practicing his limp, once in a while he would forget to limp.
http://www.devilfinder.com/find.php?q=Gunsmoke+Chester's+fake+limp

In the U K, Gunsmoke is called Gun Play.
cuhulin