Yes, that is normal. And Photoshopped pics don't show it. It's a UTILITY sink, after all.

"Sink exterior is an unpainted, ground-coat surface. Submitted

pictures are customer photos that may reflect an alteration

to the exterior, such as painting or refinishing, and may no

longer reflect the raw elements of the cast iron material as

purchased"

https://techcomm.kohler.com/techcomm/pdf/K-3203_spec_US-CA_Kohler_en.pdf

An aggressive cup wheel on a grinder would remove the nubs, then prime and repaint.

If you look closely the nubs are visible in that marketing photo, but the photo is taken at a higher angle that mostly blocks the view of the nubs. The black color also helps to disguise them.

You can see the nubs in this picture if you zoom in closer.

Also design photos get photoshopped all the time, even worse now with AI.

Designers will sometimes erase recessed light in a ceiling and lamp cords on side tables ... and then you wonder why your room doesn't look as perfect as those in "magazines" !

Well trust your gut - finally spoke to a Kohler rep and they are sending a new one agreeing it’s a defect. Most raised ridges I find online are on the bottom, not front. This is a defect.

"This is a defect."

I'm betting this is a Kohler attempt at customer satisfaction. I will be very surprised if there is any difference between the sinks. Keep us posted, please.