I adopted Schroeder in January and he had a very dull, thin coat compared to my other Mini Lop, Cotton. After being on Oxbow T for about 6 months he grew in a lush, soft, thick fur coat. So it will just take some time.
Schroeder did not shed at all for the first 5 months I had him- now he sheds normally. I think food quality plays a huge role in what their coat looks like. Schroeder was fed very cheap pellets at the petstore where he was at for adoption thru the Humane Society- and before that he was picked up as a stray. After I adopted him and got him on a proper diet he seemed to have a bigger belly- it took some time for his body condition to fill out properly. He was a bit think and had a poor haircoat (compared to what I was used to) when I brought him home- but you would never guess it now!
Even with Griffin- I have only had him about a month- and I started mixing Oxbow 15/23 into the alfalfa pellets the breeder was feeding- and in a month I have noticed he is much softer, shinier and his coat is smoother. When Griffin is older he will be switched to Oxbow T.
My adult bunnies get very limited Oxbow T pellets- about 2 Tablespoons a day- but it seems to add the extra something into their diet to keep their coats looking great (in addition to the hay and greens/vegies).