Sitting a year is not unusual. Things to look for include the battery (make sure the car starts), and the fluids should be changed if they haven't been changed for a year. If it still has the original timing belt and cooling system hoses, I would recommend changing those, but I would do so for any '91, even one that has not been sitting for a year. Other things I would look at (again, on any '91) include the snap ring status (you need to check the tranny number, although a VIN less than MT002500 means that it is unlikely to be in the snap ring range) and the window regulator status (whether the fix-it thingies or upgraded regulators have been installed). If you are not familiar with these items, check the Troubleshooting area of the NSX FAQ.
What do you mean when you say that it has not been stored properly?