The Canon LS 120PC (USB calculator, not what most of us think of as "LS-120") is fairly dopey by comparison to the Lexibook. It, too, advertises LEDs that it does not physically have.
But if NumLock is off, it simply refuses to go into "PC" mode at all, and remains stuck in calculator mode. So either one must configure NumLock to be initially set on, or have another keyboard with shared state that one can use to turn NumLock on.
It's an alternative way of handling the NumLock problem for calculator keypads. But a worse one, I think. One never has "Oh, the mode switch key isn't working because I forgot to set NumLock on. Again." moments with the Lexibook's approach.