If by "without opening the system up" you mean not logging into the system (instead of physically opening the system), look on the front of the card. There should be two stickers with part numbers. The one on the left is your base card (extension port 1-8), and the one on the right is your daughter card (trunk ports 9-12). Google this part number, or it might state it on the card. Like TTT said PRIS-U is single, PRID-U is dual.
I hope this helps, if that's what you meant.
Please remember... If it's not the way that YOU would do it, that does not necessarily mean it's wrong. EVERYONE knows SOMETHING that you do not.