Nice mod, contactcr! 
That’s a lot of rosy goodness!
Yes, ‘sw45k’ is Nichia-speak for 4500 Kelvin.
It’s part of the emitter’s ‘color rank’ specification.
Here’s a label from one of the last boxes of 219B emitters from Clemence’s group buy nearly a year ago. 
I was fortunate enough to stock up then, and I have about six lights using them. I still have some to spare for future projects, but I still get weepy thinking about my favorite LED being discontinued.
I think I’ll turn on my 219B sw45k Emisar D4 to cheer myself up. 