Your level is OK. The later models had the service lube amount adjusted to reduce incidents of axle seal leakage. It was 3.8L, and is now about 3L, or about 3/4" below the fill hole. Anywhere between 1/2" and 1" is fine.

The goo you found (and hopefully cleaned) on the drain plug and the color is normal for a first/early service. It's all the fine wear-in metal particles.