DJM is correcting their mistake and sending the correct parts, for the record.
I started doing the plugs and wires today. Since I have the front end taken apart and the wheel housings removed, it makes sense to do it now.
The plugs are definitely toast, upon inspection. I've put about 35k on the truck without changing the plugs until now, so they are at least that old. They're Delco platinums.
When it comes to spark plugs, I usually like to use copper and change them frequently. I make exceptions in situations where the plugs are hard to get to, but ours are about as easy as it gets.
It's unbelievable how long I've had the Tahoe sitting on jack stands now. A relatively quick and easy job has turned into multiple weeks of strut bumper silliness. I should have just grabbed one from a parts store in the beginning, but I just couldn't decide on which part number to use. The new package from DJM should be here soon.
Really, I could have done the A-arms and sway bar while I waited for the strut bumpers, but I've been pouting instead.