SW will still honor the cards, you just have to order something or buy from a location that is still owned by them.
The new owners would basically be giving away free merchandise by taking the gift cards since SW corporate already has the money. Kind of like trying to use a SW gift card at Cabela's. Cabela's wouldn't get any money, only a worthless card and give away the gear.
I have heard the new owners of those locations are trying to get a deal going with SW so they can honor the card's value, then bill SW corporate to get reinbursed. Also heard that they will take the cards at the customer service counter, call SW and have one of their stores ship you the items you want and not pay shipping on orders over $100. Don't know any of this first hand, only rumors.