If you achieved proper torque that is a good sign and it is probably fine.

BUT

1. Make sure the arm isn't binding against the box. It should not rub when you turn the wheel. There should be a gap between the arm and steering box/seal.
2. I would also suggest you remove the nut and make sure that the nut/washer isn't binding on the splines before it clamps the arm into the splines. After removing the nut you will not be able to simply remove the arm. It should take a puller and a little force.

If the arm isn't binding and the nut is applying all that force to the shaft/arm spline mating you are good.