You know, the stock screw/stock plate would be a great place to implement a true peep sight (ie one right next to your eye, not in the original rear sight tang.
That big bolt that holds the stock in, I bet it holds well enough that if you made some sort of adapter to fit a stock AND happen to have a peep rear sight on it, it would hold zero. Granted it would be tough to take apart, and if you switch stocks youd probably lose zero.