Help with these bleeder screws

View attachment 1715502651 View attachment 1715502652 So I’m getting ready to pull my demon out of the garage, but wanted to bleed the brakes first as it’s a new car to me and I haven’t gotten my hands on them yet. I got the rear just to eye them up and this is what I found on both sides. I feel as though there should be a screw there, not nubs. Any input on what these might be? Car had a previous life as a strip car. Thanks
Don't wast time, buy new wheel cylinders and be done!!!