They can do it all if you work them especially if you reinforce the retrieve. Currently have two pups that can do it all. They will make mistakes 100% but keep working them again and again and before you know it they will become naturals.
I started the 6 year old a couple of years ago, we have our struggles unlike the younger dogs since we introduced antlers right away to them. He is a natural freak when it comes to waterfowl/upland as well as a pointing. Year 1 we struggled but I believe it was due to his larynx paralysis...
Currently have 3 labs being trained; 6 yr, 3 yr, and 1 yr. Pretty simple process once the basic fundamentals are reenforced especially the retrieve. All three are trained to hunt waterfowl/upland/sheds and basically just rotated daily on what was being retrieved.
Another season for my labs (upland/waterfowl/sheds) is what I tell my wife! A goal of mine is collect a couple of sets of a young bull and when the time is right harvest him and be able to show his story over the years.