I asked our neighbour about the 'Yellow Sticker' on his Dodge Ram, used for pulling his 29' fifth wheel RV. Its NOT required for pulling an RV, but it is needed because he also tows a heavy duty flat bed trailer (farm and other equipment hauler). That trailer, heavy weight rating and possibly used for COMMERCIAL purposes does required the 'Yellow Sticker' and on going Annual safety Inspections.
If your Titan trailer is used for commercial purposes (or possibly could be used commercially), the Yellow Sticker (inspection) is required on both the truck and trailer, but not the fifth wheel (RV).
A lot of pickup trucks used exclusively for hauling a personal use RV will have a little red sticker on the licence plate indicating Personal Use (No Commercial).
Beverley and Ken