I buy my 219b LEDs from Andy Zhu
here is a thread that shows one sw27 compared to one sw30… (the sw30 has lower DUV)
that thread also has tests of several sw45k, and a comparison of two different sw35 (they are not identical)
we cannot specify DUV when buying, but there IS a trend imo, that sw30 and sw45k have lower DUV than SW27, sw35 and sw40