Presumably, the exotic part of the beamsplitter is that the dichroic filter must be a bandpass filter with a very narrow passband around 596nm. Yours is a high-pass filter, which wouldn't work for this application.
I am wondering if part of the reason that finding these at the frequency of sodium vapour lamps is partly due to those lights no longer being common. Or perhaps that those just aren't frequencies common to laser optics, which seems like the biggest market for these kinds of devices anyway.
Though, I see no reason why you couldn't use a laser for this process anyway, with matching notch filter.
https://www.edmundoptics.com/p/589nm-cwl-125mm-dia-hard-coat...