Not really. Remember that you have to submit to Blurb in sRGB, so even if you can't perform an absolute perfect workflow of soft proofing to the actual printer's profile, you should still have a look at how things will look in sRGB.
The issue with the “just send us sRGB but soft proof with some profile
” is you can’t control the rendering intent, BPC and really have no idea if said profile describes the process or will be used. So it is half baked. As I mentioned a few times, we have no clue about this Blurb ICC profile in terms of what it really describes.
I wonder if Adobe have missed a trick here with their implementation of soft proofing. Many users will only be interested in sRGB output, whether on the web, by email, printing by outside printers or via book publishers.
You can do this. Just select sRGB as you would any other profile. You’ll see the sRGB values and histogram you’d get IF you export in sRGB.