As long as the copper isn't touching the other wire to short it out yes you can just tape it. The plug originally had a thin piece of hard cardboard covering the screws. I see more plugs without the cardboard than I see with it. If it bothers you, it's easy enough to put another piece of cardboard on or just replace the plug. Sundial Wire carries new vintage style plugs like that one. You can probably find them other places too. Any hardware store will have a good selection of modern replacements too.
Great looking machine. The decals look nearly perfect and everything looks original.
Nice find.
Rodney