Hello,
Given the number of pieces found in the 'Waterford' pattern that have the L Kny facsimile signature mark on them it seems reasonable to make an assumption that this was a pattern that was designed for one of the aforementioned exhibitions, which was then put into production.
There are, after all too many pieces known to make it credible that they all came from these exhibitions. More probable IMHO, is that it was successful and garnered so many orders that Stuart decided to put it into production using the L Kny name. It was produced for a long period, is relatively common, and is also seen without the L Kny mark. The avant garde designs were less well supported by department store buyers, so, this design giving a nod to the more traditional is likely to have received far more commercial success.
So, did they take his name off after they finished fulfilling those orders; after he died; or, maybe, after WWII? No work on this has been done I'm afraid, however too many pieces exist to make them rarified. More desirable maybe, but whether it commands more money I guess only the market can tell.
Cheers, Nigel