Check the pictures and tell which are the repros and why?
The differences I have found:
The material of the chrome rings is slightly thinner than the original one.
The ring that holds the lamp is drilled to hold this lamp vertical, the original holds the lamp some degrees tilted.
The glass of the lamp has different markings.
The ring that holds the housing has stainless steel bolts on the repro.
The backing plate is powder coated on the repro.
But you cannot tell the difference if assembled.