I dont think the road team should be bunting. If the home team throws up a zero in the top, it's a different story. But I still don't think there is a huge difference in % chance of scoring a run with runner on second and no out vs runner on third and one out
I checked, source I was using isn't updated past 2015, but basically, runner on second and no out results in a run 61-62% of the time (this hasnt really changed going back in time, fwiw), while runner on third with 1 out scores at least a run about 65-66% of the time (again, believe it or not, this had been steady as well). This isn't a perfect comparison, because it assumes A) the bunt always gets down, and B) there's no error or anything, but it gets you in the right direction.
For total runs, runner on second and no one out gives you an average of 1.10 runs, while runner on third with one out is about 0.95 runs.