I'm not an expert on Roy's search technique, but because he usually tells us our guns shipped with checkered walnut or smooth goncolo alves, I'd think he'd pick that up quickly on the invoice.
Ivory wasn't all that expensive in the past. If you get a Shooters Bible from the 1930s, you see aftermarket suppliers selling them for $6 a set. My guess is it was cheaper to provide smooth ivory than checkered walnut.
There are legalities involved here, and any time you get political correctness involved with legislation, you get trouble. And anytime you get murky legislation, you get rampant violations, if only due to ignorance.
We like ivory as gun grips, but its also pretty common as shotgun bead sights. If you want to see real movement of ivory, attend any big antique show. It was a common item in victorian jewelry. There are still workers of ivory even today. The problem being they need to somehow assure the buyers (and the feds) that the ivory is legally in the US. That can only have happened prior to the ban on trade. One of our posters here used to supply his customers with a photo copy of the original import documents from the hunter who shot the elephant, decades ago. 10 or so years ago our gun show tables were right across from Jim Aliamo. Jim was a former supervisor of the Colt custom shop, and made grips (but only for Colts). He said that more difficult than the fabricating and production of the grips was finding and obtaining legal ivory.
His source was usually estates, where the old guy who went elephant hunting in the 1950s and 1960s passed away and his heirs didn't want the treasures. The key was keeping the paperwork from a long since forgotten vacation. Organized people apparently did that.
My understanding of the laws is that S&W could still offer ivory as an option, but they'd probably run into extreme protests from the political correctness crowd. Today you can probably find and buy a set of new production grips in the $400-500 range. I would expect S&W to need $1000 for the same grips.