Probably best not to waste time and money on rims that do not have a safety bead. These are for tubeless tyres. Earlier rims which used tubes are still fine if you mean to use tubes. These rims will have a larger hole for the valve as it is part of the tube. Current standard valves are too small for these but you can get larger pop in valves to convert the rims. It will mean no safety bead, so use at your own risk. The safety bead also keeps the bead from moving around a bit which in itself can cause loss of pressure over time. The early solid wheel was never made with a safety bead a far as I know. Early perforated rims also had no bead but the part number wasn't changed when the safety bead was added. The bead can be seen when there is a tyre on the wheel.
A good coat of paint will seal the rim if rust free. Soft paint will tend to be seal better due to the pressure so enamel likely better than baked 2 pack.