NO, usually there is no option. If it isn't in your driver control panel options than it is probably not enabled. Not saying it definitely isn't but if you can't find the option it probably doesn't exist. If you're lucky someone with a similar dell laptop can come and confirm.
Normally they are two differnt chips with 2 different drivers. You can try to go to the device manager and right click on the wireless nic and disable it. That should turn off the wifi but leave the blue tooth on.