No ball bearings. Thumbsticks are probably just Lubed plastics rubbing against eachother

So far, atleast one thing uses the IR port.

there is available a addon for the 3ds that gives you a extra pair of shoulder buttons and a second circlepad to the right.

It uses the IR port.

So supposedly the ir port allows for device to 3ds connection.

for a change, user submitted teardown with Great quality photos, Awesome!