How fun, it is good you remembered them. The black one is (I think) a Singer 66. Not uncommon, but a very good machine. I have my grandmother's in a treadle. If you check put the serial number on the front bed you can find it's model and year of production. I am not sure how to add a link, but will try. There are very good tutorials on this site for working/restoring, in the tutorial section.
http://www.ismacs.net/singer_sewing_...-database.html