I have three 7600's and one 7400 all with low mounted scopes. I took the sights of all of them. There was no change in the accuracy of the rifle with or without the open sights. I found that with extremely low magnification scopes (1.5x), the front sight was visible while looking through the scope. In my opinion, if you are not using see through mounts (which have their own problems!), the sights are just extra weight.
I suppose you could make a case for open sights being a back up in the event of a scope failure/damage. I have never had this happen to me with modern, high quality scopes. I never go on a trip with just one rifle so if I damage my scope my hint would not be over. I would just need to return to camp for the other gun.