- The safest thing to do is to buy a webcam that LG says is compatible.
- It's also safe to buy one that the sales person in the shop shows working on your model of TV.
- It's rather safe to buy one that the sales person sales should work and of course you can return it if it doesn't.
- It's totally unsafe to buy it in any other case.

For the youview box, I see it connects with HDMI. So do you want to say that your TV doesn't accept any HDMI input? Then I would return it.

Kees