Dump the factory fill AC Delco oil at about 1,500 miles. By that time it will be pretty dark. GM engines are known to darken oil early on. Step up to a better oil and no need to let dealer change the oil as they are only going to use the factory fill AC Delco Dexos 1 rated oil which is mediocre at best. Get better oil and a better filter like Mobil 1 and a Fram Ultra oil filter. Factory filter isn't good, especially if it's the AC Delco e-core filter. My recommendation is to change it at 1,500 miles and then at 3,000 miles and then follow the OLM. I dumped the factory fill ACD oil at 1,700 miles and it was blacker than tar!
By the way, GM engines don't really need much of a break-in process. I went pedal to the metal from 5 miles on the odometer and at 5,000 miles now the engine feels really smooth and very powerful!! Beat up a GM engine and it will last! Baby a GM engine and it will go to [censored] earlier on. Just my experience with GM engines over the years.