What are these holes at the bottom of the A pillars?

Hey, here's my first question to everybody!

I'm looking at the bottom of the A pillars and I'm seeing two of what look to me like screw holes. Theres no trim pieces around them so I don't know what they did and I don't see them on any other period cars I've seen pictures of.
Can someone tell me what these are? I'd like to put something in the holes to keep the elements out.