LC6 Table Knockoff?  

I bought this unmarked LC6 table today at a consignment store in Texas.  I know Cassina marks their LC6 tables with an engraved name, number, and Le Corbusier signature, but am wondering if they started that in 74 when they reissued these, or later.  I'm assuming the table is probably a knockoff, though it appears to be well made with a thick glass top.   I was reading some old threads that mentioned DWR selling Corbu knockoffs and thinking this might be one of those.  Does anyone know what years that was and if it included the LC6 tables?  The set of chairs that came with it are post-1988 Italian, and I was told they were purchased around the same time.