The UI labels pointing to the buttons appear slightly offset on the Samsung motion controllers compared to the Acer controllers. See the screenshots below and notice that the 'Main menu' points to the thumbstick instead of the menu button on the Samsung.
The gamepad.id does vary between the Acer and the Samsung controllers so it should be possible to distinguish between them.
The UI labels pointing to the buttons appear slightly offset on the Samsung motion controllers compared to the Acer controllers. See the screenshots below and notice that the 'Main menu' points to the thumbstick instead of the menu button on the Samsung. The gamepad.id does vary between the Acer and the Samsung controllers so it should be possible to distinguish between them.
Acer:
Samsung: