Those two holes are for a factory peep sight. I've read that there were some after market scope mounts made that also fit but I've never seen any. An inspired machinist could easily make up a mount to fit a red dot. The problem with finding accessories for these rifle is they have been out of production that there is none of that stuff available now, if it ever was.
Here's a picture of the sight that is mounted using the holes. You can see that by shaping some substantial sheet metal you could make a place to mount a red dot.