Hey, that relay DOES have both Normally-open and normally-closed connections although the DFROBOT page doe not show the exact connections Grr....
Just operate the relay and check the connections. I think you're all set....
See: http://datasheet.octopart.com/G5LA-14-DC12-Omron-datasheet-134281.pdf
This is a Single Pole Double Throw relay with both Normally-open and normally-closed connections.