I just became a member of Club Nintendo recently and I got quite excited when I realized that I could earn coins for owning a 3DS. I input my serial number found on the back of my 3DS, and I know that I have to input a PIN number found in the box of the 3DS to complete this process. Unfortunately I got my 3DS back in June 2010 and we basically threw the box away because we didn't see a need for it.
Is there any way I can access my PIN Number for my 3DS without having to check my now nonexistant box for it?
There is only one way to get your PIN; it is on a piece of paper included with the 3DS operations manual and Streetpass tutorials in the box. Unfortunately, there is no other way for you to get the 160 coins.
You can call Nintendo at 1800-255-3700 (6am-7pm, Pacific Time, 7 days a week) to see if they will make the 3DS survey (which is what actually gives you the 160 coins after you input the PIN) available to you, since you do have the serial number registered. That, however, is completely up to them.