Yep, I did mine the first time with the covers on too, but then got a set of black crinkle painted ones.
During the process of changing the valve covers, I noticed how easy it was to access the spark plugs, and in particular ensure that all 12 coil to plug wires were firmly seated on the plugs.
( I have the squiggly Magnecor wires, they are really hard to seat if the covers are on )