I just now got to see bearcatfb30's pup. Honestly, the pup looks more like a solid tan/red GSD. We have a member here who has a GSD that is pure red/tan with a black mask. This pup reminds me of that dog. I can see some darkening along the back in the second pic, so maybe the photos are leading me wrong.
Bear, I think your pup is likely to remain lightly colored for life. In fact, it's a general rule that pups lighten with age- even adults can lighten. I think some sables are different, but don't be surprised if your dog changes colors a few times before he's fully grown!