yes they are called rock guards,finding a sunline replacement is gonna be tough,your best bet would be to measure what size you need then hit some dealers and measure some new units (any manufacturer),then when you find one that will fit have them order the stone guard and all the mounting hardware.the other option would be to search the web for rv salvage yards then call aroundand see if anyone has it.
05 sunline 267sr
01 F-250 V-10 4x4 Lariat supercab SB auto 4:30 LS
draw-tite 1200# trunnion wd,friction sway control,prodigy
happy camping Rich,Maryellen,Josh and Jake