After eight years with this new engine and 3,700 miles, I pulled the plugs. I'm not having any noticeable problems, but would like to hear from others what might be going on after looking at the spark plug wear.
It's a 4/7 swap, so explanation of the firing order in the picture. Starting from driver side front - to back then passenger front-to-back
Hard to tell with your lighting, but 4 looks the leanest and, next would be 7,6 and 1 for lean. The rest of the bunch look normal. If it's running good, spend 12 bucks on some new Delco plugs slap them in and forget about them for the next 8 years.
Might want to put the old ones back in, then run a can or 2 of seafoam through the engine to clean any carbon build up on the backs of the intake valves, then put the new plugs in.