Depends upon the age. Those made back in the early 80s were really questionable as to quality. The ones from the late 80s on were of better quality but be sure to bring a pencil with you to make sure the cylinder is in time (drop the eraser side down the barrel. If it clears the cylinder and makes it to the firing pin the cylinder is in time. If it stops at the forcing cone or hits the cylinder sides instead of the hole, you've got a problem).

Also, check the Blue Book for reasonable values.