I don't think there would be a problem with mounting a harris onto that stud. I see your concern with it, but I don't think it's going to be a big deal.
You can see how the surface mates up with the stock. Being that curved shape should allow it to center nicely on the stock even though that nub is there. But i'm in no way positive about that. I'm just speculating. You could have clearance issues too, as I'm sure you aware of, but i've looked for a 1712 stock with bipod before twice now and haven't been able to turn anything up.