To answer this, you’ll need to figure out your Bluetooth antenna situation. Bluetooth uses the same 2.4GHz RF band that b/g/n Wi-Fi uses. Some systems’ antenna designs share antennas between Bluetooth and Wi-Fi, but the systems are carefully designed to make sure this can be done without one clobbering the other all the time.
In the original design/configuration of your laptop, one of those two Wi-Fi antenna leads didn’t have a transmitter hooked up to it. That lead might be combined with a lead from the Bluetooth module and attached to a shared antenna. Or the Wi-Fi Rx-only antenna and the Bluetooth Tx/Rx antenna could be separate, but placed so close to each other that there's not enough separation to allow Bluetooth to successfully receive Bluetooth traffic while the Wi-Fi card transmits Wi-Fi traffic on its nearby antenna (in the original setup, this wasn’t a problem, because the Wi-Fi radio chain hooked up to that antenna was Rx-only).
If you donÆt care about Bluetooth, never use it, and don’t mind keeping the Bluetooth radio turned off at all times, you don’t need to worry about this.
Other than that, it should work fine, if your new card fits the space, if your antenna leads can reach to where your new card's U.FL connectors are, if your new card’s EMI, power, and thermal profiles doesn't screw up other things in your system, etc.
Cards generally can’t detect whether antennas are connected or not, so they assume they’re connected and try to act to the card’s full capabilities.