Just off the top of my head, Ahrends was the only grip maker I can think of that made a wood non-finger-groove boot grip, but I don't think they're accepting orders. I think they've gone out of business, IIRC. You might be able to find some for sale online somewhere, like eBay, maybe.

I think just about every maker of boot grips makes them with finger grooves.

Altamont may have some options.

Culina Grips may be able to accomodate you.

I'm not sure, but I think Craig Spegel might be able to make a set of his boot grips without finger grooves, but I could be wrong. Also, his wait list is over 1 year, I think. Maybe 2 years by now.

They're not wood, but the plastic PGS Hideout Grips are available without finger grooves. I had a set for my K-frames, and I actually liked them better than the Ahrends grips I had. Very trim, but feels good in the hand. A good choice for smaller hands. And they're only about $20 from Brownells or you can order direct from the manufacturer if Brownells is out of stock. Something to consider, maybe as a temporary option 'til you can get something nicer?

Edit: I just checked Badger Grips, out of curiosity. It looks like you can get wood boot grips for the K-frame round butt and have them custom-ordered without finger grooves for an extra fee. Maybe worth checking out.