My guess would be they are not factory grips.
Don't remember ever seeing one NIB with white stocks. Course, I haven't seen them all.....
Got any PICs?
Shop Ruger has grips in stock now if you want something different.
I would think they are Ruger, have medallion in them just like factory wood. they are not smooth, they have checkering molded into them. I have saw the white smooth, but have not noticed the checkered.