Shop owner is saying that the key was probably replaced and has backlit logo on it and the laptop doesn't have backlit. I am not entirely sure that his statement is right or wrong. Could it be the case that some L440 have backlit and some doesn't i.e. 2 variants of this tinkpad?
PSREF implies that no L440 should have a backlit keyboard. Which makes sense the L series are the cheap models so I'd expect them to not have it. Especially since the *40 was one of the first series to even offer backlit keyboard.
T440 for example says:
Keyboard UltraNav 6-row, spill-resistant, multimedia Fn keys, optional LED backlight