If the pulley doesn't wobble, that's good. If the pulley hasn't slid backwards into the timing cover, that's real good. If the pulley hasn't moved forwards running the belts at an angle, that's real good too. If it passes the 3 part test, don't bother to change it unless it does one of the 3.
I had to replace one on a 670T and I dont recall any notches on either the old one or the replacement. My recollection is the engine was running a little ragged with no visible symptoms as mentioned in the other post.
We have replaced the damper pulleys on our 7040, 8010 and M2 w_2900 engine all in the past 5 years. All had turned on the hub; the combine had also slid into the timing gear cover. After replacing the 8010 pulley I did notice smoother operation. All of the pulleys we replaced had alignment marks - just a center-punch mark on the pulley and one on the hub.
We had a 7045 that spun n1 rod bearing. It had been breaking alternator brackets and went through several alternator internal parts. The timing marks were lined up pretty close but the rubber was swelled on one side. Apparently this set up a viberation in the crank. The top half of the bearing was wrapped around the thrust sides of the rod and the bottom half was in relatively good shape. All of the other bearings were in perfect shape. Also in the service manual for both a 2590 Case and my 8200 John Deere they recomend replacing the balancer after a certain number of hours. I have not seen that for the Allis. I would replace it with a new one. Mark Heitmann has a supplier that rebuilds used ones. That could be an option. His Number is 715-673-4829
keep a watch on it, as stated, but do not trust it for timing. If in question use a piece of solder inserted in n1 inj hole and determine true TDC. Feel the piston go up and when it stops make a mark on the pulley and continue turning til it starts down and make another mark, halfway 'tween the two is TDC. See if this coincides with the timing marks. This is a very important check on all rubber dampners. We find about 50% of the ones we check from damaged engines off. Usually the crank stopped suddenly - and the outer pulley did not.