I had the same issue after installing an 06 5.3 in my 89 Silverado. Almost all of my plugs looked like that. Not sure this helps you (not sure what engines or years were the problem) but I was told to change my drivers side valve cover. There is a new design with a baffle that stops the PCV system from sucking excessive oil and putting it in the intake. Mine had the same smoke on start up and more oil consumption (about a quart every 350 miles) Once I changed the valve covers (I just did both), problem solved. Look up the new valve cover design and you will find more information about it. Hope this helps because it was pretty simple to fix.