The metal part is the connector; if you are close to the router you might have some functionality but it probably is pretty poor. I think yes, you need to replace them, there is some degree of protection built in but I wouldn't court on it being enough with no antennae attached, operating wifi without them may, (probably will) damage the internal circuitry. If it IS working at a distance from the router I will be very surprised and stymied too. Do you "have to" no, not if you never try to use the wifi. Good luck, and happy fixing!