Type in "Hitches" in your search area on this forum and you will find all kinds of good info on this subject.
The short of it is, no, Heartland will not warranty any damage caused by any add-on hitches, or brackets or racks that may cause undue stress to the RV. However, practically speaking, dealers install them for people all the time and they go on to enjoy years of care-free use of their RVs.
ST