iFixit

The main chips on the mini-PCIe wireless card include:

Broadcom BCM4322 Intensi-fi® Single-Chip 802.11n Wi-Fi Transceiver

Broadcom BCM20702 Single-Chip Bluetooth 4.0 Processor with Bluetooth Low Energy (BLE) support

BLE chips hold many advantages over classic Bluetooth including 128 bit AES security, 6 ms latency (classic Bluetooth is 100 ms), and less power consumption.

It's interesting that there's a spot for stamping the revision and serial number, but that Apple chose not to stamp a unique number on it.