Since the Huey has raised rivets on the hull, You have 2 choices. Both of them are pain in the a...
#1 If you have enough pations take a 0.3 mm sterene rod from Evergreen and cut as many pieces (1mm) as you need and then glew them on the hull
If there are not too many of them to be recreated - it won't be so annoing.
#2 Use alluminium foil. Cut out exact shape and size of the panel where rivets are missing. Then turn it upside down, put it on pack of news papers and make resessed rivets with the needle. Dont press to hard not to penetrate the foil. Turn it back and glew the foil on hull. This method is really hard - I myself tryed it only on small panels - but it works awesome! Just need some practice.
Check this out
Here is Dacota in 1/72!!!!
All panels and rivets on them made with foil method
http://www.sukhoi.ru/forum/attachment.php?attachmentid=45993
http://www.sukhoi.ru/forum/attachment.php?attachmentid=46843
http://www.sukhoi.ru/forum/attachment.php?attachmentid=46844
http://www.sukhoi.ru/forum/attachment.php?attachmentid=45994
http://www.sukhoi.ru/forum/attachment.php?attachmentid=45995
Good luck