I wrote:
I think I'll go with Liberation Sans Bold and/or
Liberation Sans Narrow
Bold. They look close enough, other than having a horizontal base bar
for the "1", and I think I can live with that.
Here's a PDF showing an ELF switch panel with Liberation Sans Bold:
http://www.brouhaha.com/~eric/retrocomputing/elf/panel.pdf
The inner circles for the switches are the 250 mil diameter hole, and
the outer circle show the size of a typical internal lock washer that
would be used.