Those welded on nuts (the ones with the 4 weld nubs) look to be for sheet metal screws (pointed coarse thread). You'd have to get a size assortment to be sure which size is proper. Hard to tell from photos. Should be available at any hardware store. You could get round head slotted or phillips or hex head. The ones on the left of your first photo look like they might be machine thread screws. Also available at a local hardware.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
Basically the same items on both Jim and Tim's links. Hardware is pretty universal over the years. But either of those pages gets you to the type of hardware used. They aren't that specific as to where they're used in many cases, though.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.