Body plug holes?

Hi all -

I am re-doing the carpet in my '78 280z which entails sanding some rust, POR15 sealer, dynamat, etc.

When I took off the carpet and sound deadener, I found these two holes that look like they're supposed to have body plugs, but don't. Any idea if these are supposed to stay open, or if there are plugs that are supposed to be in here, are they're available at a local parts store? These are in the passenger side footwell to the left of the fuse box. The one on the left is at the beginning of the transmission tunnel and the one on the right is through the firewall.

NOTE: I've boxed both holes in blue with arrows pointing to them. The gray shown on the left side is just the lighting - that is a hole.