People call this the "break in oil," but here's the deal: When you build or rebuild any engine, you apply special grease to all of the bearings. Usually, these are molybdenum-based lubricants, and the engine oil washes most of this grease away as soon as the engine is used. I don't know if it takes 10 miles or 1,000 miles... but you get the idea; the oil "washes" this grease out of the bearings. It is this assembly grease that mixes with the motor oil and causes the first oil drain to be so dark. It would probably look this way after 200 miles.Same here, did my first oil change at 1k and plan to do another at 3k. The oil was incredibly dirty at the 1k mark, so I'm glad I changed it out.
As far as I know, there's no harm in keeping this grease inside the crankcase for 1,000 or 5,000 miles. There is very little of this grease in the engine, but it's enough to discolor the motor oil. There may be other coatings on the internal engine components which also get washed off by the motor oil, such as rust inhibitors which prevent corrosion between component fabrication and engine assembly, but I don't know. I'm also of the school of an early oil change on a new car, but I've never read a technical manual recommend or require it.