The innards of the Pebble are unsurprisingly very simple, with the multicontroller unit, three-axis accelerometer and Bluetooth radio all contained on a single board alongside other support components.
One surprise noted in the teardown is that the Bluetooth radio does not appear to conform to the 4.0 low-energy protocol (BLE) claimed in its specs. The Panasonic PAN1316 RF module used in the Pebble is supposed to contain Texas Instruments' CC2564 Bluetooth controller, which supports BLE, but iFixit found a CC2560A chip that does not support BLE inside the package. Pebble had previously noted that it was using a chip that would support BLE but that it would not ship with support enabled, promising that it would be added via a software update at a later date.
The good news for Pebble owners is that opening it is unlikely to be necessary: the battery is expected to last for ten years, and the watch strap can be replaced without opening the watch.
Update 9:26 AM: iFixit has updated its article and Pebble has posted on Reddit to confirm that BLE support is indeed possible.
Many chip vendors make silicon consistent between product lines but simply flash different firmware to enable features. Our chips were labeled CC2560 because TI asked us if we wouldn't mind using them with CC2564 firmware to speed up our order. Pebble most definitely has Bluetooth LE support, though it has not yet been enabled in our operating system.