have not heard of genuine T3S/MT3S with no lip…
Most of the clones I have don't claim to be Kanger including a few with the lip.
It's possible that the ones w/o the lip that claim to be Kanger are clones too, but that shop claims they are genuine.
They clearly not the other clone they sell so it would be odd for them to not do so for the T3S tanks.
I don't know of a good way to detect fakes of the T3S tanks.