If bike is stock you may need to adjust the pilots a little, but rejet is not required for altitude adjustments. Shadows are jetted quite lean from the factory. Most of my recreational riding is done 5000-8000 feet, I'm jetted rich, no issues. Granted I live at 300 feet.
93 VT1100C Sleeper, VH Exhaust, Saddleman Seat, Baby Apes, Metzlers, 2mm sleeved and bored (1150cc),10.5:1 comp, Modified Heads, Valves, Cams, Adjustable Timing, Bored Carbs.