I got the price match with the $20 GC (and an extra $7 off with the Target card) with just the print ad at the Culver City, CA Target. The cashier even walked me up to the front to check with the manager and he said that I indeed should get the gift card because it is a different transaction or something like that. It was a quick transaction regardless.

The cashier scanned the 3DS and GC before applying the price match if it makes a difference.