Close but not quite. In some cases the threads will wear slightly and will need a small additional rotation to reach the same torque, or if the threads are now contaminated with rust or grease, anti-seize, etc, this can also effect turns to reach the desired torque value.
As far as making a seal on fittings, in some cases you use tape or pipe dope. In some cases the first time you put the parts together, the seat was new and the first installation deforms them a bit so you may need to use some emery cloth or whatever to true the mating surface.