no. they simply describe the functions available on the printer.
this allows the interface to display those printer options to you.
for PS compatible printers this is enough, you select the options
and the document, with the selected options, are passed along to the
printer. for non-PS printers the options are passed to the backend
processor which produces the relevant commands for that printer.
with CUPS you'll (most likely) have ghostscript as a backend processor.
this comes with support for a good range of printer backends (e.g.
PCL) as well as being easily extensible with vendor processors (like
the hpijs processor from HP).
with lpd and apsfilter you process the incoming text or latex file
into postscript. this works fine if the printer supports PS. if not
then you'll pipe that postscript onto ghostscript which will then
process the PS into the native printer language (e.g. PCL).
