Definitely.Originally they were fitted in the days of the black powder rifles because the face of the actions would burn away and pit really badly.This gave you a chance to effectively replace the face of the action that the cartridge was against and make it servicable again.It also gave you a chance to correct any off centre striking issues.
I forgot about those as all the side by side shotguns I make have them and I take them for granted.The one thing is that the striker diameters are different for a rifle.Normally a shotgun is around .100" and a rifle is .060"-.070".You also have to watch the striker protrusion.I normally do the shotguns and rifles to around .055".This is more critical on a rifle and really shouldn't be more than .060".On a shotgun I've seen them at .080" and they've been fine.Also the rebound on a rifle is quite critical.If the rebound allow's the striker to dissapear back into the striker hole as soon as the cartridge is fired,then the primer will volcano back into the striker hole because of the pressure.You need to have the striker still protruding slightly so the primer has nowhere to go.

I could write a book on all these bit's that people have no idea about.The're all important,but unless you do these things all the time and see what happens to the firearms through all stages of production your very unlikely to know.