Yes, it needs to be registered. You can have your local dealer call Tohatsu America to update the owner information for that model/serial.
In all fairness, we seldom see any warranty issues on these. Most problems are caused by owner neglect or misuse.
Keep the oils changed every 50 hours or annually. Use non-synthetic 10w-30 FC-W oil in the crankcase.
Replace water pump kit every 3 years in cold fresh water -- more often if run in silty water.
Flush the motor after any run in salt/brackish water.
Run the carb out at the end of the day, unless planning to run again tomorrow, to reduce varnishing.
Run only non-ethanol fuel if possible. Never ever more than 10% ethanol.