I am pretty positive that the baffled valve covers have baffles welded or bolted to the inside of the cover blocking oil from getting directly to the hole. If you covers dont have baffles you can buy baffled grommets to do the same thing, I dont know how well they work though. If you do have baffles drill a hole in the one you plan to put oil through or you may be there all day pouring oil. You want a baffle anytime the hole it going to be used to vent the covers (to air cleaner, standard breather or pcv), if using for oil fill and you plug the hole with a fill cap then you shouldnt need a baffle.
I purchased a set of Billet Specialties valves covers and it came with these baffles that bolts to the inside of the cover. The one on the left is how it comes, the one on the right is how I modified it to flow oil in faster.
I am pretty sure you're not going to be using an egr with your setup, but for those who are changing valve covers and have egr you may need to purchase another egr spacer and gaskets to raise the egr enough to clear the taller valve covers. Also if you are using stock exhuast manifolds with sheet metal cover for heat into the air cleaner then you need to remove the heat sheild (sheet metal) from the passenger side exhuast manifold or taller and thicker flange valve covers will not fit.