Seriously, 'rounding' choils and spines really is one of the over-rated selling points of more expensive knives, and hyped up a bit too much in my opinion. Nice to have and a lot more comfortable, but dead easy to do yourself in a number of ways.
Knives made for foreign sales from Japan increasingly have the rounding done, by request of foreign sellers who use this as a selling point (justifying higher prices), or because due to this influence buyers request it. However, I'd presume that knives have been sold in Japan for years typically without the coveted rounding because it's pretty much a no-brainer as to how to smooth bits off yourself.
All suggestions above sound fine to me, which shows how reasonable and simple it is to do. I wouldn't make much of it: just some appropriate sandpaper, maybe use natural slurry or powder with that if you want, or other powder, and hold the knife and do it by touch, or secure it somehow, just as you might when restoring kasumi finish on the sides, or at first use stones or other to establish the shape you want, and then use sandpaper or equivalent to complete. Who knows, you've probably just saved yourself at least 50 bucks.