Edit: after reading your entire post it looks like that is for the 4cyl. I dont have any experinece with that motor. You should edit your sig. and put you vehicle info.

Is this a gen1 3.0 v6? If so, you dont really have to. But when you put the timing belt back on you will need to line up the marks. Each cam sprocket has a little dimple on one spot. There should also be a stamped line on the metal part above the sprocket. The dimples should be pointing almost all the way up. The crank pulley will have a little cut out around the outer lip, this lines up with the zero on the degree thing on the plastic timing belt cover. Hard to describe, but if you look you will see it and it will all be clear.

Also when you put the distributor back in, you have to line up the marks on that too while the timing marks are lined up. Common porblem when putting everything back on.