yes, you will have to pay 7% GST for anything you ship in, regardless if it's a gift, purchase, lucky draw prize, or something dropped from the sky.
i paid GST for stuff my friends sent me...and they declared the actual amount for insurance purposes.
sure, you can declare your $3000 85/1.2 as $380, but if something goes wrong, insurance only covers a portion of the $380 you declared.
and i don't think BH photo will do such things. it is actually illegal and comitting fraud to under-declare items for tax purposes.
bottomline, do what you want, don't get caught. after you get caught, don't post in lopitiam to make noise and whinge.