Are you asking about a grab handle outside by the door to assist walking up/down the steps or a grab handle for the shower/tub?
If you are asking about an outside grab handle, my dealer has installed them on my last two TT's. My first one did not come with the larger swing out grab handle. They installed it, but I paid for the handle.
My second TT (current TT) only had one on the front door, so we purchased a second one and had the dealer install it on the back door leading in to the bathroom.
HAPPY CAMPING!! :D
Daryl and Sandy
2013 Eagle 314BDS
2012 Ford F150 Platinum, 4 x 4 Crew Cab with Ecoboost