The 4,303 number is the "dry weight" that it weighed when it left the factory with all the installed options and the LP tanks empty. There should be a sheet pasted inside the closet door in the bedroom with that number. The 5,500 number is the GVWR (Gross Vehicle Weight Rating) which is the maximum it can weigh fully loaded. That accounts for the capacity of the tires, springs, and axles and frame.
Gene & DW Ginny
2002 Sunline T-2363
2008 Toyota 4-runner 4wd 4.7L V-8
Reese Dual Cam straightline - P3 Brake controller